Şerb, Ioan. “Critères Pour La Convexité d’ordre N Des Fonctions: Criteria for N-Convexity of Functions”. Anal. Numér. Théor. Approx. 5, no. 1 (February 1, 1976): 97–111. Accessed December 4, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1976-vol5-no1-art10.