@article{SIGMA_2008_4_a63,
     author = {Fr\'ed\'eric Butin},
     title = {Hochschild {Homology} and {Cohomology} of {Klein} {Surfaces}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2008},
     volume = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2008_4_a63/}
}