TALPUR, Mir Munsif Ali et al. Isolation and Characterization of Soil Fulvic Acid. Pakistan Journal of Analytical & Environmental Chemistry, [S.l.], v. 17, n. 1, p. 10, june 2016. ISSN 2221-5255. Available at: <http://pjaec.pk/index.php/pjaec/article/view/53>. Date accessed: 17 may 2022.