NARESH KUMAR, K., et al. “Quantitation of Protopine in Fumaria Parviflora L. Whole Plant Powder by High-Performance Liquid Chromatography”. Asian Journal of Chemistry, vol. 21, no. 9, Mar. 2010, pp. 6695-00, https://asianpubs.org/index.php/ajchem/article/view/12136.