Gutlyanskii, V.Ya., O. Martio, V.I. Ryazanov, and M. Vuorinen. “Infinitesimal Geometry of Quasiregular Mappings”. Annales Fennici Mathematici 25, no. 1 (February 1, 2000): 101–130. Accessed April 13, 2025. https://afm.journal.fi/article/view/134971.