SENOUSSI, B., & BEKKAR, M. (2015). Helicoidal surfaces with Δ ᴶ ᵣ = Ar in 3-dimensional Euclidean space. Studia Universitatis Babeș-Bolyai Mathematica, 60(3), 437–448. Retrieved from https://studia.reviste.ubbcluj.ro/index.php/subbmathematica/article/view/5796