@Article{ micfrapao02, author = { Gori, Michele and Maggi, Francesco and Marcellini, Paolo }, title = { On some sharp conditions for lower semicontinuity in $L^1$ }, journal = { Differential and Integral Equations }, year = { 2003 }, volume = { 16 }, pages = { 51-76 }, URL = { http://cvgmt.sns.it/paper/1087/ }, note = { cvgmt preprint} }