Please be aware of - and where appropriate, lend your support to - this Individual Engagement Grant proposal https://meta.wikimedia.org/wiki/Grants:IEG/PlanetMath_Books_Project which I've put together with PlanetMath contributor Raymond Puzio.
Inspired by the PlanetMath Exchange project on Wikipedia, our aim with this proposal is to improve the PlanetMath platform and make it easy to produce mathematics textbooks, for export to places like Wikibooks.
Your endorsement of the grant proposal would mean a lot!
Please note: although we are targeting English initially in with the proposal (as a demo), this will be relevant to other language communities as well. I've announced the project on the English anguage Wikibooks, but if you can spread the word to other language communities, please do.
Let me know if you have any questions as well!
Joe