Assertiveness as an important social competence positively affecting employee relations [elektronický zdroj] / Malgorzata Sierpińska .
In: Business management - practice and theory in the 21st century / Manažment podniku - prax a teória 21. storočia [1 CD-ROM (833 s.)]. -- Nitra : Slovak University of Agriculture, 2013. -- ISBN 978-80-552-1026-1. -- S. 584-587
http://www.slpk.sk/eldo/2013/zborniky/032-13/se3/Sierpinska.pdf .