With regard to
a4, a quote from the english version of
l2tabu will do:
1.1 a4.sty, a4wide.sty
Do not use these ‘two’ packages any longer. You should delete them
without replacement from your LaTeX source. Use the class option
a4paper instead. Speaking in terms of typography these packages, or
others similar to these do not provide good layout. What is even
worse, there is more than one version of these packages around, and
different versions of those packages are incompatible with one
another, providing deviating settings for page margins. So you may not
trust that your document will look the same—or just as bad? – when
being compiled on someone else’s system when exchanging LaTeX source.
Replace: a4.sty, or a4wide.sty by class option
aeguill, see Philippe Goutet' s answer to Are ae and aeguill only needed when using CM fonts?