Lv, Pin, Zimin Wei, Zhimin Yu, Jizhou Zhang, and Limin Wang. 2019. “Heavy Metal Contamination in Soils of Greenhouse Vegetable Production Systems in a Cold Region of China”. International Journal of Agricultural and Biological Engineering 12 (2):98-102. https://www.ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/4306.