2008

Yin, R. K. (2008), Case Study Research: Design and Methods , Sage Publications .

2005

George, A. L. & Bennett, A. (2005), Case Studies and Theory Development in the Social Sciences , MIT Press .

Lund, B.; Hammond, T.; Flack, M. & Hannay, T. (2005), 'Social Bookmarking Tools (II): A Case Study - Connotea', D-Lib Magazine 11 .