Bujňák, Lukáš, u. a. „Effect of Supplemental Humic Acid With Urea As a Non Protein Dietary Nitrogen Source on Rumen Variables in Sheep“. Animal Welfare, Etológia és Tartástechnológia (AWETH), Bd. 16, Nr. 1, Mai 2020, S. 1-7, https://doi.org/10.17205/SZIE.AWETH.2020.1.001.