PARKKONEN, Jouni; PAULIN, Frédéric. A classification of $\mathbb{C}$-Fuchsian subgroups of Picard modular groups. Mathematica Scandinavica, Berkeley, CA, United States, v. 121, n. 1, p. 57–74, 2017. DOI: 10.7146/math.scand.a-26128. Disponível em: https://journals.msp.org/mscand/article/view/310. Acesso em: 24 jul. 2026.