@article{1103898966,
author = {Pegoraro, Francesco},
title = {Three applications to $SO(4)$ invariant systems of a theorem of L. Michel relating extremal points to invariance properties},
journal = {Comm. Math. Phys.},
volume = {40},
number = {1},
year = {1975},
pages = { 41-64},
language = {en},
url = {http://dml.mathdoc.fr/item/1103898966}
}
Pegoraro, Francesco. Three applications to $SO(4)$ invariant systems of a theorem of L. Michel relating extremal points to invariance properties. Comm. Math. Phys., Tome 40 (1975) no. 1, pp. 41-64. http://gdmltest.u-ga.fr/item/1103898966/