KARDJILOVA, Krassimira - PULOV, Vladimir - POPOV, P. Measuring planck’s constant in a physics laboratory experiment using LEDs1. In PRAE 2011 : proceedings of scientific works 149 s. ISBN 978-80-552-0662-2. . Nitra : Slovak University of Agriculture, 2011, s. 62-66. Dostupné na internete:<http://www.slpk.sk/eldo/2012/zborniky/004-12/Kardjilova.pdf>