Nenov, N. “ON THE VERTEX FOLKMAN NUMBERS $F_v(\underbrace{2,. ,2}_R;R-1)$ and $F_v(\underbrace{2,. ,2}_R;R-2)$”. Ann. Sofia Univ. Fac. Math. And Inf., vol. 101, Dec. 2013, pp. 5-17, https://stipendii.uni-sofia.bg/index.php/fmi/article/view/226.