@Article{ carleatom01, author = { Carriero, Michele and Leaci, Antonio and Tomarelli, Franco }, title = { Necessary Conditions for Extremals of Blake & Zisserman Functional }, journal = { C. R. Math. Acad. Sci. Paris, }, year = { 2002 }, volume = { 334 }, pages = { 343-348 }, URL = { http://cvgmt.sns.it/paper/449/ }, note = { cvgmt preprint} }