@article{SMJ2_2008_34_3_a2,
     author = {Bouali, S. and Ech-chad, M.},
     title = {Generalized {D-Symmetric} {Operators} {I}},
     journal = {Serdica Mathematical Journal},
     pages = {557--562},
     publisher = {mathdoc},
     volume = {34},
     number = {3},
     year = {2008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SMJ2_2008_34_3_a2/}
}