Modelling of e-learning processes: an approach used in Plovdiv e-university. - George Totkov; Elena Somova; Mariana Sokolova (CompSysTech, 2004)

Accumulative question types in e-learning environment. - Mariana Sokolova; Georgy Totkov (CompSysTech, 2007)

Extended IMS specification for accumulative test system. - Mariana Sokolova; Georgy Totkov (CompSysTech, 2008)

A software frame for modelling and runtime control of adaptive testing. - Hristo Indzhov; Mariana Sokolova; George Totkov (CompSysTech, 2010)