Wan, L., and S. Gupta. “A Presentation of the Automorphism Group of the Two-Generator Free Metabelian and Nilpotent Group of Class $c$”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 54, no. 6, June 2002, pp. 771-9, https://umj.imath.kiev.ua/index.php/umj/article/view/4115.