@article{01932959, title = {Hasse invariant and group cohomology.}, journal = {Documenta Mathematica}, volume = {8}, year = {2003}, pages = {43-50}, zbl = {1044.11030}, language = {en}, url = {http://dml.mathdoc.fr/item/01932959} }
Edixhoven, Bas; Khare, Chandrashekhar. Hasse invariant and group cohomology.. Documenta Mathematica, Tome 8 (2003) pp. 43-50. http://gdmltest.u-ga.fr/item/01932959/