Bujňák, L. et al. 2020. 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). 16, 1 (May 2020), 1–7. DOI:https://doi.org/10.17205/SZIE.AWETH.2020.1.001.