Illig, J.; Hotho, A.; Jäschke, R. & Stumme, G. (2011), A Comparison of Content-Based Tag Recommendations in Folksonomy Systems, in Karl Erich Wolff; Dmitry E. Palchunov; Nikolay G. Zagoruiko & Urs Andelfinger, ed., 'Knowledge Processing and Data Analysis' , Springer, Berlin/Heidelberg , pp. 136--149 .