There are six document styles and style options available that are not described in the manual: the proc style option for making camera-ready copy for conference proceedings, the bezier option for drawing curves, the ifthen option for implementing if-then-else and while-do control structures, the letter style for making letters, the showidx option for printing index entries in the margin, and the makeidx option for use with the MakeIndex program. See Section for further information on the MakeIndex program that uses the makeidx option.