Split a complex LaTeX document into separate pieces.
This style file allows a possibly complex LaTeX document to be split amongst several input files, which are LaTeXed (or even hand-produced!) entirely independently, whilst still synchronising a specified list of counters, and allowing cross-references, citations, and indexing commands to be used in a consistent way.
I haven't touched this for quite a while, so I'm no longer sure that it'll work with recent versions of LaTeX (that is versions since LaTeX2.09!). I don't see any reason why it won't, however, so it should still be worth looking at. If you do get it working with LaTeX2e, or have to modify it to make that work, please let me know. Good luck!