VALACH, Michal - HÍREŠ, Ľubomír. Examination of viscosity and specific heat of combustion of biofuels. In PRAE 2011 : proceedings of scientific works,. Nitra : Slovak University of Agriculture, 2011. ISBN 978-80-552-0662-2. , s. 138-140. Dostupné na internete:<http://www.slpk.sk/eldo/2012/zborniky/004-12/Valach-Hires.pdf>