PotapenkoI. V. “Relationship Between Normalized Tensors of Two Regular Networks on the Surfaces in the Euclidean Space $E_3$”. Ukrains’kyi Matematychnyi Zhurnal 68, no. 2 (February 25, 2016): 271-277. Accessed December 5, 2020. http://umj.imath.kiev.ua/index.php/umj/article/view/1839.