Fabian Abel Ivana Marenzi Wolfgang Nejdl Sergej Zerr Sharing Distributed Resources in LearnWeb2.0. 154-159 2009 EC-TEL http://dx.doi.org/10.1007/978-3-642-04636-0_16 conf/ectel/2009 db/conf/ectel/ectel2009.html#AbelMNZ09