Khadzhiivanov, Nikolay, and Nedyalko Nenov. 2004. “LETTER TO THE EDITOR. TURAN’S THEOREM AND MAXIMAL DEGREES”. Ann. Sofia Univ. Fac. Math. And Inf. 96 (December):173-74. https://ftl5.uni-sofia.bg/index.php/fmi/article/view/171.