@article{01959281,
title = {On signatures and a subgroup of a central extension to the mapping class group.},
journal = {Homology, Homotopy and Applications},
volume = {5},
year = {2003},
pages = {251-260},
zbl = {1054.57022},
language = {en},
url = {http://dml.mathdoc.fr/item/01959281}
}
Natov, Jonathan. On signatures and a subgroup of a central extension to the mapping class group.. Homology, Homotopy and Applications, Tome 5 (2003) pp. 251-260. http://gdmltest.u-ga.fr/item/01959281/