Claus-Peter Klas Norbert Fuhr Sascha Kriewel Hanne Albrechtsen Giannis Tsakonas Sarantos Kapidakis Christos Papatheodorou Preben Hansen László Kovács András Micsik Elin K. Jacob An experimental framework for comparative digital library evaluation: the logging scheme. 308-309 2006 conf/jcdl/2006 JCDL http://doi.acm.org/10.1145/1141753.1141822 db/conf/jcdl/jcdl2006.html#KlasFKATKPHKMJ06