@Article{ alb05a, author = { Alberti, Giovanni }, title = { Distributional Jacobian and singularities of Sobolev maps }, journal = { Ricerche Mat. }, year = { 2005 }, volume = { 54 }, number = { 2 }, pages = { 375-394 }, URL = { http://cvgmt.sns.it/paper/1158/ }, note = { cvgmt preprint} }