@article{LJM_2002_10_a0,
     author = {B. Aqzzouz and M. Kadiri},
     title = {Infinite dimensional extension of {A.\,P.~Calder\'on's} theorem on positive semidefinite biquadraric forms},
     journal = {Lobachevskii journal of mathematics},
     pages = {3--8},
     publisher = {mathdoc},
     volume = {10},
     year = {2002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/LJM_2002_10_a0/}
}