Hata H, Todo T, Onoue S, Matsumoto K. Characteristics of Sustainable OSS Projects: A Theoretical and Empirical Study. In Proceedings of the Eighth International Workshop on Cooperative and Human Aspects of Software Engineering [Internet]. Piscataway, NJ, USA: IEEE Press; 2015. pp. 15–21. http://dl.acm.org/citation.cfm?id=2819321.2819325