@article{AFM_1991_16_1_a14,
     author = {A. Hinkkanen},
     title = {Sense-reversing generators of discrete convergence groups in the plane},
     journal = {Annales Fennici Mathematici},
     pages = {179--182},
     publisher = {mathdoc},
     volume = {16},
     number = {1},
     year = {1991},
     doi = {10.5186/aasfm.1991.1612},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.1991.1612/}
}