Ivan, M. “Sur Les Surfaces Du Type Bernstein-Bézier composées: On the Compounded Bernstein-Bézier Type Surfaces”. Anal. Numér. Théor. Approx., vol. 15, no. 2, Aug. 1986, pp. 127-30, https://ictp.acad.ro/jnaat/journal/article/view/1986-vol15-no2-art5.