Not sure it helps, anyway I've searched for Planeshift on Sciencedirect and found these results (despite my academic access I wasn't able to read the contents so I can't tell what's inside but hey, it's peer-reviewed stuff!):
1.
Free/Open Source Software Development: Recent Research Results and Methods
Advances in Computers, Volume 69, 2007, Pages 243-295
Walt Scacchi
2.
Prototyping
Game Design Workshop (Second Edition), 2008, Pages 175-212
Tracy Fullerton, Christopher Swain
Oh, there are also some results on Google Books, but anyone can search there

(I really hope PS will get its wiki page back: I found it that way)
[
EDIT: I've just discovered anyone can search on Sciencedirect too
: http://www.sciencedirect.com/ - well, it's an input anyway]