“On the Transformations Preserving Asymptotic Directions of Hypersurfaces in the Euclidean Space”, Eur. J. Pure Appl. Math., vol. 2, no. 4, pp. 564–573, Oct. 2009, Accessed: Nov. 23, 2024. [Online]. Available: https://www.ejpam.com/index.php/ejpam/article/view/459