@article{701495,
     title = {On certain class of unitarizable representations of the Lie algebra $u(p,q)$
               },
     booktitle = {Proceedings of the Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {1991},
     pages = {[207]-215},
     mrnumber = {MR1151907},
     zbl = {0752.17004},
     url = {http://dml.mathdoc.fr/item/701495}
}

Molev, A. I. On certain class of unitarizable representations of the Lie algebra $u(p,q)$
               , dans Proceedings of the Winter School "Geometry and Physics", GDML_Books,  (1991), pp. [207]-215. http://gdmltest.u-ga.fr/item/701495/