[texhax] Cross-refs across separate books

[Robin Fairbairns]

> I am writing two separate collections of notes for two related courses I 
> am teaching. I am using book.cls for both of them, and each of them 
> obviously has its own sectioning and equation numbering.
> 
> However, since the two works frequently make reference to each other, I 
> would like to cross-reference \label's defined in one LaTeX file within 
> the other LaTeX file, via usual \ref's.
> 
> I guess I can do that by including file1.aux in file2.tex (and vice-versa) 
> at an appropriate point, and be careful with multiply defined labels and 
> other possible conflicts. I should also run latex on each file a 
> sufficient number of times, in order to achieve consistency among all 
> labels.

see http://www.tex.ac.uk/cgi-bin/texfaq2html?label=extref

you're forgiven for not finding that: i searched the faq for it, and
only found the reference because i knew the answer ;-)

i really must do something about faq searching one day...