Ali, M. U., M. Z. Haque, M. A. A. Maruf, and M. A. A.-. Sakia. “Mass Fragmentation Pattern of Some Mono- and Di-Substituted Formamidines. Part-1. Mass Pattern of 1-Arylformamidines”. Biological Sciences - PJSIR, vol. 48, no. 6, Dec. 2005, pp. 386-8, https://v2.pjsir.org/index.php/biological-sciences/article/view/1429.