SEITZ, Heiko. Accounting options and limits in quantitatively determining the added value of human resource management. In Business management - practice and theory in the 21st century. 1. vyd. 1 CD-ROM (833 s.). ISBN 978-80-552-1026-1. Manažment podniku - prax a teória 21. storočia. Nitra : Slovak University of Agriculture, 2013, s. 574-583. Dostupné na internete:<http://www.slpk.sk/eldo/2013/zborniky/032-13/se3/Seitz.pdf>