Ahmadi, B., and H. Doostie. “Fibonacci Lengths of All Finite $p$-Groups of Exponent $p^2$”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 65, no. 5, May 2013, pp. 603–610, https://umj.imath.kiev.ua/index.php/umj/article/view/2444.