Johnson johnson-74 describes ...
In a recent study [#!johnson-74!#], it is described as ...
Howells howells-66-pop discussed the subject briefly ...
In a further article [#!howells-66-var!#], greater attention was
given ...
Johnson and Howells johnson-howells take a different view ...
This work [#!johnson-etc!#] quotes ...
Elsewhere [#!anon-67!#] it is shown ...
Howells [p. 29]howells-66-var describes ...