@code{t} and @code{nil} without surrounding punctuation. For example:
@example
- CODE can be ‘lambda’, nil, or t.
+CODE can be ‘lambda’, nil, or t.
@end example
@noindent
@item
Try to avoid using abbreviations such as ``e.g.'' (for ``for
example''), ``i.e.'' (for ``that is''), ``no.'' (for ``number''),
-``c.f.'' (for ``in contrast to'') and ``w.r.t.'' (for ``with respect
+``cf.'' (for ``in contrast to'') and ``w.r.t.'' (for ``with respect
to'') as much as possible. It is almost always clearer and easier to
read the expanded version.@footnote{We do use these occasionally, but
try not to overdo it.}