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- Network Working Group H. Alvestrand
- Request for Comments: 1502 SINTEF DELAB
- August 1993
-
-
- X.400 Use of Extended Character Sets
-
- Status of this Memo
-
- This RFC specifies an IAB standards track protocol for the Internet
- community, and requests discussion and suggestions for improvements.
- Please refer to the current edition of the "IAB Official Protocol
- Standards" for the standardization state and status of this protocol.
- Distribution of this memo is unlimited.
-
- 1. Introduction
-
- Since 1988, X.400 has had the capacity for carrying a large number of
- different character sets in a message by using the body part
- "GeneralText" defined by ISO/IEC 10021-7.
-
- Since 1992, the Internet also has the means of passing around
- messages containing multiple character sets, by using the mechanism
- defined in RFC-MIME.
-
- This RFC defines a suggested method of using "GeneralText" in order
- to harmonize as much as possible the usage of this body part.
-
- 2. General principles
-
- 2.1. Goals
-
- The target of this memo is to define a way of using existing
- standards to achieve:
-
- (1) in the short term, a standard for sending E-mail in the
- European languages (Latin letters with European accents,
- Greek and Cyrillic)
-
- (2) in the medium term, extending this to cover the Hebrew and
- Arabic character sets
-
- (3) in the long term, opening up true international E-mail by
- allowing the full character set specified in ISO-10646 to be
- used.
-
-
-
-
-
-
- Alvestrand [Page 1]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- The author believes that this document gives a specification that can
- easily accomodate the use of any character set in the ISO registry,
- and, by giving guidance rules for choosing character sets, will help
- interworking.
-
- 2.2. Families of character sets
-
- 2.2.1. ISO 6937/T.61
-
- ISO 6937 is a code technique used and recommended in T.51 and T.101
- (Teletex and Videotex service) and in X.500, providing a repertoire
- of 333 characters from the Latin script by use of non- spacing
- diacritical marks. It corresponds closely to CCITT recommendation
- T.61.
-
- The problem with that technique is that the character stream comes in
- two modes, i.e., some characters are coded with one byte and some
- with two (composite characters). This makes information processing
- systems such as an E-mail UA or GW more complex.
-
- It is also not extensible to other languages like Korean or Chinese,
- or even Greek, without invoking the character set switching
- techniques of ISO 2022.
-
- 2.2.2. ISO 8859
-
- ISO 8859 defines a set of character sets, each suitable for use in
- some group of languages. Each character in ISO 8859 is coded in a
- single byte.
-
- There are currently 11 parts of ISO 8859, plus a "supplementary" set,
- registered as ISO IR 154. Most languages using single-byte characters
- can be written in one or another of the ISO 8859 sets. There are
- sets covering Greek, Hebrew and Arabic, but there is still
- controversy over the problem of the rendering direction for Hebrew
- and Arabic.
-
- All the ISO 8859 sets include US-ASCII as a subset. All use 8 bits.
-
- ISO 8859 is regarded by many as a solution; for instance, the X
- windows system now comes with ISO-8859-1 as the "standard" character
- set, with the possibility of specifying others. But since the same
- applications often do not support character set switching within
- text, it is problematic to use these in a truly multilingual
- environment. (Also, most fonts claiming to be "ISO- 8859-1" in X11R5
- are actually 7-bit fonts. The implied lie is very unfortunate.)
-
-
-
-
-
- Alvestrand [Page 2]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- It turns out to work fine, however, if the second language is
- English, since this can be written in all ISO 8859 sets.
-
- The parts 3 and 4 have not seen wide acceptance, and it is expected
- that they will be discarded. They should therefore not be used.
-
- Note that an ISO 8859 set is actually 2 sets in the ISO sense: US-
- ASCII in the G0 set and another character set in the G1 set. The
- overloading of the word "character set" is unfortunate, but
- traditional.
-
- 2.2.3. ISO 10646
-
- At the moment of writing, ISO 10646 has just been accepted as an
- International Standard. It is basically a 32-bit character set, with
- all of the currently used characters being numbered by the first 16
- bits, leaving some room for expansion.
-
- It is not possible to use ISO 10646 as a normal character set,
- because it does not conform to the rules for usage of byte values set
- down in ISO 2022 and other places; it uses the "control space" for
- (parts of) graphic character codes.
-
- There are a number of ways to encode ISO 10646 characters "on the
- wire". There are methods within the ISO 2022 standard to switch to
- these, either as "other coding system without return" or as "other
- coding system with return" (that is, you can go back from it to the
- one you came from using an ISO 2022 escape sequence).
-
- The following registrations have been made:
-
- ISO 10646 UCS-2 Level 1 has been registered with ESC 2/5 2/15 4/0,
- ISO 10646 UCS-4 Level 1 has been registered with ESC 2/5 2/15 4/1,
-
- The following are applied for:
-
- Reg# Escape sequence Standard/Sponsor Description
- 174 ESC 2/5 2/15 F ISO/IEC 10646 UCS-2, Level 2
- 175 ESC 2/5 2/15 F ISO/IEC 10646 UCS-4, Level 2
- 176 ESC 2/5 2/15 F ISO/IEC 10646 UCS-2, Level 3
- 177 ESC 2/5 2/15 F ISO/IEC 10646 UCS-4, Level 3
- 178 ESC 2/5 F ISO/IEC 10646 UTF-1
-
- << NOTE: The registration numbers for UCS-2 level 1 and UCS-4
- level 1 are not known. Neither are the assigned final characters
- for the other sets. Information requested!>>
-
-
-
-
-
- Alvestrand [Page 3]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- This character set will become very important in the future, but at
- the moment, few systems are able to support this directly.
-
- The GeneralText body part can be used for carrying any of these
- character sets.
-
- 2.3. Body parts that can be used in X.400
-
- At the moment, no established way of transferring a full set of
- characters in X.400-based E-mail exists. In the future, it is likely
- that a new body part, based in ISO 10646, will be available, or
- GeneralText may be able to use ISO 10646, but this matter has not yet
- been clarified.
-
- In the short term, the deployed and available body parts are:
-
- (1) IA5Text
-
- (2) For X.400/84: ISO6937Text and Teletex
-
- (3) For X.400/88: GeneralText
-
- IA5Text is the method of choice for E-mail that contains only
- characters from IA5 (equivalent to US-ASCII).
-
- The ISO6937Text body part is defined in the ISO DIS documents
- corresponding to X.400(84) [10]; these never became a standard, so
- they are now quite difficult to find. It is in principle limited to
- using text that can be presented in ISO 6937, but since ISO 6937
- refers to the ISO 2022 method of changing character sets, it is
- theoretically possible to use any ISO registered character set, but
- there is no facility for announcing the character sets used. This
- makes interworking with equipment that does not support the same
- character sets complex.
-
- It is still, however, the only body part suitable for carrying non-
- paginated text in non-basic character sets in X.400(84).
-
- Teletex, which is identical in all versions of the X.400 standard,
- has the same problem of implicit ISO6937, but has the added problem
- that it also specifies a page format, with, for instance, a left
- margin of 5 character positions. This is often not desirable.
-
- The details of Teletex are specified in recommendation T.51 and its
- relatives.
-
- GeneralText is defined in ISO 10021-8, the part of [9] that
- corresponds to CCITT recommendation [11]. It is an Extended body
-
-
-
- Alvestrand [Page 4]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- part, so no modification to CCITT implementations is needed to carry
- it.
-
- GeneralText is suitable for interchange, since it has got proper
- announcement facilities. It can use any number of character sets, and
- announces them both in the Encoded Information Types of the X.400
- envelope and the parameters of the body part.
-
- We recommend this body part for carrying unformatted text in
- X.400/88.
-
- 3. GUIDELINES FOR THE GENERATION OF GENERALTEXT
-
- 3.1. Formal definition of GeneralText
-
- A GeneralText message is a byte stream that contains characters and
- character switching sequences according to [12].
-
- The X.400 ASN.1 definition of the GeneralText body part is:
-
- general-text-body-part EXTENDED-BODY-PART-TYPE
- PARAMETERS GeneralTextParameters IDENTIFIED BY id-ep-general-text
- DATA GeneralTextData
- ::= id-et-general-text
-
- GeneralTextParameters ::= SET OF CharacterSetRegistration
-
- CharacterSetRegistration ::= INTEGER (1..32767)
-
- GeneralTextData ::= GeneralString
-
- The definition is from ISO/IEC 10021-7 [9], Annex I, with
- modifications made in the MHS Implementor' Guide, version 8, chapter
- 3.6.3, bullet F130. It does not appear in the CCITT version of the
- standards.
-
- 3.2. Brief description of ISO 2022 character set switching
-
- There are 4 graphic character sets active at any time in a
- GeneralText message, called G0, G1, G2 and G3. In addition, there are
- 2 control character sets, called C0 and C1.
-
- At any moment, one of the sets G0-G3 is active in code positions 2/1
- to 7/14, and another is active in code positions 10/0 to 15/15. The
- setting is achieved by so-called "locking shift" sequences.
-
- (Formally, code positions 2/0 and 7/15 are reserved for "space" and
- "DEL" respectively, and only 94-character character sets can be used
-
-
-
- Alvestrand [Page 5]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- in G0. In practice, this restriction is sometimes ignored)
-
- Single characters from the non-active sets may be invoked by the use
- of "single shift" sequences.
-
- The control character sets always occupy the code positions 0/0 to
- 1/15 (C0) and 8/0 to 9/15 (C1).
-
- The character sets currently active as G0-G3 and C0-C1 may be changed
- using "character set designating sequences".
-
- At the beginning of a GeneralText message, one must always assume
- that set 2 (IA5) is active as G0, shifted into the lower half, that
- set 1 (standard) is active as C0, and that no G1-G3 or C1 set is
- invoked. This is specified in the definition of "GeneralString" in
- [5], the definition of ASN.1 encoding (section 23.5.2).
-
- If this is not a suitable initial state, a message must always start
- with the necessary announcers and escape sequences to designate and
- invoke the character sets that are actually used. The character sets
- in use may be changed later in the message by use of escape
- sequences.
-
- The parameters of a GeneralText message always list all the character
- sets used, by quoting their ISO reference numbers.
-
- It is impossible to use a character set not registered with ISO in a
- GeneralText message.
-
- It is also impossible to decide on the true meaning of a byte in a
- GeneralText message without scanning the whole message for shift and
- escape sequences.
-
- 3.3. How to use the character sets
-
- RECOMMENDATION:
-
- When the text to be rendered is representable in one of the character
- sets of ISO-8859, the G0 set should be set to ISO 646 International
- Reference Version (1991), also called US-ASCII, ISO-IR-6.
-
- The older character set ISO-IR-2, ISO 646 IRV(1983), should NOT be
- used. This means that the escape sequence ESC 2/8 4/2 (designating
- US-ASCII as G0) should always occur at the beginning of the message.
-
- The G1 set should be set to the character set identified by the
- relevant ISO-8859 part. G2 and G3 are not used.
-
-
-
-
- Alvestrand [Page 6]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- This corresponds to the first level of ISO 4873 usage.
-
- For the currently defined parts of ISO 8859, the character set
- designations for the G1 set are (relative to ISO 8859:1987):
-
- Part ISO IR name Escape sequence Remarks
- for G1 use
-
- 1 ISO-IR-100 Esc 2D 41 West Europe (Latin-1)
- 2 ISO-IR-101 Esc 2D 42 East European (Latin-2)
- 3 ISO-IR-109 Esc 2D 43 (Latin-3)
- 4 ISO-IR-110 Esc 2D 44 (Latin-4)
- 5 ISO-IR-144 Esc 2D 4C Cyrillic
- 6 ISO-IR-127 Esc 2D 47 Arabic
- 7 ISO-IR-126 Esc 2D 46 Greek
- 8 ISO-IR-138 Esc 2D 48 Hebrew
- 9 ISO-IR-148 Esc 2D 4D Turkish (Latin-5)
- 10 ISO-IR-157 Not listed Sami (Latin-6)
-
- The escape sequence for 8859-10 (Latin-6) is not listed in RFC 1345.
-
- NOTE: The use of ISO 8859-3 and ISO 8859-4 is NOT recommended if
- other possibilities exist.
-
- NOTE: There is a debate about the Arabic and Hebrew character sets.
- These languages are normally read right to left, but encodings have
- been done in both "visual" (left to right) and "phonetic" (right to
- left) ordering, there is significant disagreement about what the
- "right" way to do it is, and the character sets mentioned do not
- specify it. So, one should be careful not to use these character sets
- until a standard is agreed upon, or the result will probably be
- unreadable (siht ekil).
-
- (Note that there is some confusion as to what parts are actually
- standardized; the Norwegian standards institute reports that only
- part 1, 2, 3, 4, 6, 7 and 8 are currently standards. Other reports
- claim that both 8859-10 and 8859-11 are standards, and I definitely
- think that 8859-9 is.)
-
- NOTE: ISO has not ruled out the possibility of changing the ISO 8859
- standard. This would involve changing the registry information in
- this table, so this should be assumed valid for ISO 8859 versions
- that are current in 1993.
-
- The G1 set should be permanently shifted into the upper half of the
- code page.
-
-
-
-
-
- Alvestrand [Page 7]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- When the text is not representable in one of the ISO-8859 character
- sets, the following rules may be applied:
-
- (1) If any Latin characters are used, keep IA5 as the G0 set.
-
- (2) If a mainstream character set is used (Greek, Cyrillic,
- Hebrew, Arabic), designate this as the G1 character set,
- and permanently shift this into the upper half of the code
- page (LS1R).
- EXCEPTION: The Japanese community has a long tradition of
- switching between the Japanese 16-bit character set
- ISO-IR-87 and US-ASCII as the G0 set. See [7]
- for details. If ISO-IR-87 is used, that technique should be
- used instead of the one recommended here.
-
- (3) If occasional extensions to a character set that is
- basically Latin occur (like accents, national variants
- and so on), and these are available in a single character
- set, designate the relevant set as G2 and use single
- shift (SS2) to invoke characters from this character set.
-
- The ISO 8859 supplementary set, ISO-IR-154, is recommended
- for this purpose.
-
- This corresponds to the ISO 4873 "second level" application.
-
- (4) If two non-Latin character sets are used, the second should
- be designated as G3, and shifted into the upper half of the
- code page by the use of Locking Shift 3 Right (LS3R).
-
- This corresponds to the ISO 4873 "third level" application.
-
- (5) If avoidable, use of character sets with floating accents,
- like ISO 6937, should be avoided.
-
- (6) The shifts changing the lower half of the code table (SI/SO,
- LS2 and LS3) should NOT be used.
-
- RATIONALE: Keeping the G0 set reserved for US-ASCII will ensure that
- text in US-ASCII has the same bit representation always.
-
- The use of the upper code page for other scripts ensures that both
- text in these languages and text of this type mixed with English can
- be represented without the use of shift sequences.
-
- If the language and/or content of a text is completely unknown,
- chapter 5 gives an algorithm that may be used to decide upon the
- character sets. This might, for instance, be suitable for use at
-
-
-
- Alvestrand [Page 8]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- automatic mail gateways.
-
- NOTE: At the time of this writing, few applications that use ISO 4873
- level 2 and level 3 encoding exist. It has been estimated that
- implementing them in an application that already uses a rich
- repertoire of characters is a matter of programmer-days, not
- programmer-months, but this has not been proven.
-
- 4. GUIDELINES FOR THE RENDERING OF GENERALTEXT
-
- As a basic rule, one should NOT assume that any of the rules above
- are followed.
-
- An user agent capable of rendering GeneralText should:
-
- (1) ALWAYS be able to identify and render characters in IA5, no
- matter how they are designated and invoked.
-
- (2) ALWAYS be able to identify and render characters in the
- "native" character sets, no matter how they are designated
- and invoked.
-
- (3) ALWAYS indicate the presence of characters that cannot be
- adequately represented on the current output device.
-
- (4) NEVER render a character in an unknown or unrepresentable
- character set by displaying the character in the same bit
- position in the native character set.
-
- (5) PREFERABLY be able to identify and render characters that are
- the same as characters in the "native" character sets, even
- though they are designated and invoked as part of other
- character sets. This applies in particular to the
- "invariant" part of ISO 8859, parts 1 through 6.
-
- (6) PREFERABLY be able to combine the floating accents of ISO
- 6937 with their base characters for suitable rendering using
- the capabilities of the current output device.
-
- (7) PREFERABLY be able to display text both in a mode using
- fallbacks for nonrenderable characters and in a mode
- designating nonrenderable characters as such.
-
- (8) PREFERABLY be able to save the content of a GeneralText
- message to a file or other suitable media, saving all
- character set information, for later processing by other
- means. It is not illegal to render the character set
- information into a different format; however, it should be
-
-
-
- Alvestrand [Page 9]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- noted that it is easy to lose vital information if the format
- chosen for representing character sets does not offer the
- possibility of referencing all character sets in the ISO
- registry of character sets.
-
- These requirements also apply to gateways that transform the message
- into some other format, for example a gateway that transforms a
- message into MIME using [7] for the purpose.
-
- 5. RECOMMENDATION FOR SELECTION OF CHARACTER SETS
-
- 5.1. Algorithm for selection of character sets
-
- When one has text in which characters from several character sets
- occurs, and wants to process this into a GeneralText document, it is
- often hard to guess right at the character sets to select.
-
- The following paragraphs give an algorithm that can be started at the
- beginning of a message, and at the end of it, return a set of
- character sets that can be used as G0..G3 character sets, OR an
- indication that the task is impossible.
-
- VARIABLES:
-
- UsedSets
- The set of character sets that MUST be used for this message
-
- UsableSets
- The set of character sets that MAY be used for this message.
- Each set also contains a counter for each character position.
-
- PossibleSets
- The set of all the character sets known to be usable in the
- destination format.
-
- ALGORITHM:
-
- 1) Add IA5 (ISO-IR-6) to the UsedSets (as G0).
-
- 2) Get the next character of the text. If the text is
- completely analyzed, go to FINISHED
-
- 3) If it is in the UsedSets, go to 2).
-
- 4) Find the set of character sets from PossibleSets in which the
- character occurs. If it does not occur in any, report
- failure.
-
-
-
-
- Alvestrand [Page 10]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- 5) If it is in a single character set in PossibleSets only, add
- this set to UsedSets, and go to 2).
-
- 6) If it is in more than one character set, add these to
- PossibleSets (if not already present), and increment the
- counter for that character in all the sets. Go to 2).
-
- FINISHED)
-
- 1) (FINAL SELECTION) Remove any character set in UsedSets from
- PossibleSets.
-
- Zero the counters for any character in PossibleSets that also
- occurs in UsedSets.
- WHILE (more characters left)
- Select one character set and move it from PossibleSets to
- UsedSqets.
- Zero the counters for all characters in this set in the other
- PossibleSets.
- END WHILE
- This step can be "tuned" any way you want, for instance by
- choosing the character sets most likely to be understood at
- the destination first, choosing the character sets covering
- the most characters first, avoiding multi-byte character sets
- as long as possible, or any other scheme suitable for the
- application.
-
- 5.2. WHAT TO DO ON FAILURE
-
- Failure will occur in this schema if a character is found that is not
- in the PossibleSets. It may then be handled in one of the following
- ways:
-
- (1) Replace the character with the SUB control character
-
- (2) Replace the character with Keld Simonsen Mnemonics [8].
- This is a reversible transformation as long as the
- recipient is aware that it has been used, but requires
- passing out-of-band information to indicate this.
-
- (3) Replace the lost characters with any suitable fallback or
- mnemonic scheme intended for human understanding
-
- (4) Bounce the message/refuse the conversion/give up.
-
- The action to be taken may be different based on the percentage of
- "lost" characters.
-
-
-
-
- Alvestrand [Page 11]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- If the message has "controls" like "conversion with loss prohibited",
- only the last possibility may be used.
-
- 5.3. RECOMMENDED CHARACTER SETS
-
- There are 2 steps in the algorithm above that are left for local
- judgement:
-
- (1) Selection of the sets to appear in PossibleSets.
-
- (2) The algorithm for deciding which character set to select in
- step 9.
-
- In the context of generating X.400 GeneralText messages, the
- following is recommended:
-
- Sets in PossibleSets:
- ISO-IR-6 Esc 28 42 (G0) US-ASCII, IA5, ISO646
- ISO-IR-100 Esc 2D 41 (G1) ISO-8859-1 West Europe
- ISO-IR-101 Esc 2D 42 (G1) ISO-8859-2 Central/Eastern Europe
- ISO-IR-144 Esc 2D 4C (G1) ISO-8859-5 Cyrillic
- ISO-IR-127 Esc 2D 47 (G1) ISO-8859-6 Arabic
- ISO-IR-126 Esc 2D 46 (G1) ISO-8859-7 Greek
- ISO-IR-138 Esc 2D 48 (G1) ISO-8859-8 Hebrew
- ISO-IR-148 Esc 2D 4D (G1) ISO-8859-9 Turkish
-
- The following multi-byte character sets are recommended:
-
- ISO-IR-87 (Japanese JIS C6226-1983) Esc 24 29 42 (G1)
- ISO-IR-149 (Korean KS C 5601-1989) Esc 24 29 43 (G1)
- ISO-IR-58 (Chinese GB 2312-80) Esc 24 29 41 (G1)
-
- It is a STRONG recommendation that character sets not listed above,
- which do not add any new characters to the total set of characters
- given by the character sets above, should NOT be used in X.400
- interchange.
-
- ISO-IR-87 is the Japanese character set that is allowed in a Teletex
- string, such as the subject field.
-
- NOTE: ISO-IR-87 has been "superseded" by ISO-IR-168, which allows two
- extra Kanji characters. Any application that handles ISO-IR-87 should
- also be able to handle ISO-IR-168.
-
- Algorithm for selecting character sets:
-
- Start at the top of the list above, and add each set only if it is
- needed.
-
-
-
- Alvestrand [Page 12]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- 6. REFERENCES
-
- [1] Information technology - ISO 8-bit code for information
- interchange - Structure and rules for implementation, Third
- edition, 1991-12-15.
-
- [2] Information technology - 8-bit single-byte coded graphic
- character sets (parts 1-11; the parts have different dates, the
- ones referenced here are from RFC 1345).
-
- [3] Information technology - Coded graphic character set for text
- communication (parts 1 and 2; part 2 dated 1983-12-15).
-
- [4] Code for the representation of names of languages. 1988 version.
-
- [5] CCITT Recommendation X.209(1988): Specification of Basic
- Encoding Rules for Abstract Syntax Notation One (ASN.1).
- Technically aligned with ISO 8825 and ISO 8825/AD 1.
-
- [6] Information Technology - Universal Multiple-Octet Coded
- Character Set (UCS) - ISO 10646.
-
- [7] Murai, J., Crispin M., and E. van der Poel, "Japanese Character
- Encoding for Internet Message Bodies", RFC 1468, Keio
- University, Panda Programming, June 1993.
-
- [8] Simonsen, K., "Character Mnemonics & Character Sets", RFC 1345,
- Rationel Almen Planlaegning, June 1992.
-
- [9] Information Technology - Text communication - Message- Oriented
- Text Interchange Systems (MOTIS) - ISO 10021 - October 1988.
-
- [10] ISO DIS documents describing X.400/84 with slight extensions.
- Now very hard to get copies of, since they failed to become
- ISes.
-
- [11] CCITT Recommendation X.420 (1988), Interpersonal Messaging
- System.
-
- [12] International Standard--Information Processing-- ISO 7-bit and
- 8-bit coded character sets--Code extension techniques, ISO
- 2022:1986.
-
- 7. Security Considerations
-
- Security issues are not discussed in this memo.
-
-
-
-
-
- Alvestrand [Page 13]
-
- RFC 1502 X.400 Use of Extended Character Sets August 1993
-
-
- 8. Author's Address
-
- Harald Tveit Alvestrand
- SINTEF DELAB
- N-7034 Trondheim
- NORWAY
-
- EMail: Harald.Alvestrand@delab.sintef.no
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- Alvestrand [Page 14]
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