# How to reference list items in another TeX document?

Problem in a nutshell: I would like to reference items in an external LyX document (containing a list of definitions and theorems).

Problem in detail: I am a Math student. I maintain a LyX document containing a numbered list of definitions and theorems. I often add, delete and modify this document. I would like to treat this document as a database and reference it in other LyX documents like I do with in-document cross-references to definitions, theorems, etc. How can this be accomplished?

Variations:

1. I'm open to solutions that go beyond LyX.
2. I'm open to solutions that require making the list of definitions available in some form other than a LyX document (e.g. a database).

Software used: LyX + MiKTeX + BibTeX on Windows 7

My level of LaTeX proficiency: Beginner+

-
`xr` package may help. –  Leo Liu Jan 1 '12 at 8:47
Thanks, Leo Liu. –  Itai Jan 1 '12 at 9:01