Kong, Du-Lin, Ming-Shu Wu, Chang-Ri Han, Jing-Ya Ma, and De-Hui Wan. 2011. “Synthesis and Characterization of a-Aminophosphonic Acids Containing Adenine”. Asian Journal of Chemistry 23 (7):2871-73. https://asianpubs.org/index.php/ajchem/article/view/10518.