@article{ELA_2011__22__a45,
     author = {El Kadiri, Mohamed},
     title = {Sur une classe de formes biquadratiques semi-d\'efinies positives},
     journal = {The electronic journal of linear algebra},
     pages = {513--520},
     publisher = {mathdoc},
     volume = {22},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ELA_2011__22__a45/}
}