KAPLAN, MUSTAFA, SAHRIYE SONMEZ, ERSIN POLAT, and HALIL DEMIR. 2010. “Effects of Organic and Mineral Fertilizers on Yield and Nutritional Status of Lettuce”. Asian Journal of Chemistry 20 (3):1915-26. https://asianpubs.org/index.php/ajchem/article/view/19170.