A Framework for Licensed Digital Signatures. - Alper Ugur; Ibrahim Sogukpinar (NetCoM, 2009)

An X.509 Based Licensed Digital Signature Framework for Hierarchical Organizations. - Alper Ugur; Ibrahim Sogukpinar (WiMo, 2010)

Sayısal imzada kurumsal yetki modeli (Institutional authorization model on digital signatures) - Alper Ugur (2016)