Duca, Dorel I. “On Some Types of Optimization Problems in Complex Space”. Anal. Numér. Théor. Approx. 10, no. 1 (February 1, 1981): 11–16. Accessed April 11, 2025. https://ictp.acad.ro/jnaat/journal/article/view/1981-vol10-no1-art2.