Maxscript language reference (help menu, maxscript language reference from inside 3ds max)
http://docs.autodesk.com/3DSMAX/16/ENU/MAXScript-Help/index.html?url=files/GUID-914BC0D0-CC30-4B72-849D-5D34205B985D.htm,topicNumber=d30e34835
Algorithmic Beauty of Plants:
http://algorithmicbotany.org/papers/abop/abop.pdf