J. Hopfner in E. Protner, Ur., Education from the Past to the Present: Pedagogical and Didactic Lessons from the History of Education, let. ZORA 62. Univerzitetna založba Univerze v Mariboru, 2009. Pridobljeno: 1. marec 2026. [Na spletu]. Dostopno na: https://old.press.um.si/index.php/ump/catalog/book/85