KATRANDZHIEV, Nedyalko. Prediction of apples' internal transmittance - utopia or a reality ? In PRAE 2011 : proceedings of scientific works 149 s. ISBN 978-80-552-0662-2. . Nitra : Slovak University of Agriculture, 2011, s. 72-78. Dostupné na internete:<http://www.slpk.sk/eldo/2012/zborniky/004-12/Katrandzhiev_2.pdf>