@Article{ garnes02, author = { Garroni, Adriana and Nesi, Vincenzo }, title = { Rigidity and lack of rigidity for solenoidal matrix fields }, journal = { Proc R Soc London A }, year = { 2004 }, volume = { 460 }, number = { 2046 }, pages = { 1789-1806 }, URL = { http://cvgmt.sns.it/paper/1040/ }, note = { cvgmt preprint} }