@article{CMUC_2012__53_3_a2,
     author = {Dr\'apal, Ale\v{s} and Shcherbacov, Victor},
     title = {Identities and the group of isostrophisms},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {347--374},
     publisher = {mathdoc},
     volume = {53},
     number = {3},
     year = {2012},
     mrnumber = {3017835},
     zbl = {1258.20056},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_2012__53_3_a2/}
}