@article{RSMUP_1993__89__103_0,
     author = {Albar, Muhammad A. and Al-Hamdan, Walid M.},
     title = {The triangle groups},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {103--111},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {89},
     year = {1993},
     mrnumber = {1229047},
     zbl = {0818.20032},
     language = {en},
     url = {http://www.numdam.org/item/RSMUP_1993__89__103_0/}
}