@article{oai:repository.dl.itc.u-tokyo.ac.jp:00040243, author = {Funar, Louis Louis}, issue = {4}, journal = {Journal of mathematical sciences, the University of Tokyo}, month = {}, note = {application/pdf}, pages = {599--646}, title = {On the Groupoid of Transformations of Rigid Structures on Surfaces}, volume = {6}, year = {1999} }