Popoviciu, Elena. “Sur Certaines propriétés Des Fonctions Quasi-Convexes (I): On Certain Properties of Quasi-Convex Functions (I)”. Anal. Numér. Théor. Approx. 12, no. 2 (August 1, 1983): 175–186. Accessed May 18, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1983-vol12-no2-art9.