ANIRUDH P. SINGH AND M.K. NAUTIYAL, Vandana Naithani. Spectroscopic Characterization of Humic Acids Extracted From Different Type of Soils of Punjab. Journal of the Indian Society of Soil Science, India, v. 65, n. 1, 2017. Disponível em: https://epubs.icar.org.in/index.php/JISSS/article/view/70251. Acesso em: 19 oct. 2025.