Lakhani KR, Wolf R. Why hackers do what they do: Understanding motivation and effort in free/open source software projects. In: Feller J, Fitzgerald B, Hissam S, Lakhani KR, editors. Perspectives on Free and Open Source Software. MIT Press; 2005. Download: lakhaniwolf.pdf (67.75 KB)
Hissam S, Weinstock C. Open Source Software: The Other Commercial Software. In: 1st Workshop on Open Source Software Engineering at ICSE 2001.; 2001. Abstract  Download: hissamweinstock.pdf (21.32 KB)