Open Textbook Initiative. The The American Institute of Mathematics (AIM) has developed evaluation criteria to identify the open source textbooks that are suitable for use in traditional university courses. The Editorial Board maintains a list of approved textbooks which have been judged to meet these criteria.
MathBook XML is a lightweight XML application for authors of scientific articles, textbooks and monographs that incorporates the best of DocBook, LaTeX, and HTML. When a document is written in MathBook XML, it is possible to quickly produce print, PDF, web, EPUB, Sage Notebooks, and iPython Notebooks from a single source.