Dang, T. “DETERMING LEAD IN SOIL BY EXTRACTION-PHOTOMETRIC IN CAO LANH CITY, DONG THAP PROVINCE”. TRA VINH UNIVERSITY JOURNAL OF SCIENCE; ISSN: 2815-6072; E-ISSN: 2815-6099, Vol. 7, no. 25, June 2019, pp. 56-59, doi:10.35382/18594816.1.25.2017.121.