Einat Amitay David Carmel Nadav Har'El Shila Ofek-Koifman Aya Soffer Sivan Yogev Nadav Golbandi Social search and discovery using a unified approach. 199-208 2009 Hypertext http://doi.acm.org/10.1145/1557914.1557950 conf/ht/2009 db/conf/ht/ht2009.html#AmitayCHOSYG09