@article{02221860, title = {The Johnson homomorphism and the second cohomology of }, journal = {Geometry \& Topology}, volume = {5}, year = {2005}, pages = {725-740}, doi = {10.2140/agt.2005.5.725}, zbl = {1085.20016}, language = {en}, url = {http://dml.mathdoc.fr/item/02221860} }
Pettet, Alexandra. The Johnson homomorphism and the second cohomology of . Geometry & Topology, Tome 5 (2005) pp. 725-740. doi : 10.2140/agt.2005.5.725. http://gdmltest.u-ga.fr/item/02221860/