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@article{MAT_1966_10_2_a2, author = {G. Biriuk and E. A. Coddington}, title = {Normal extensions of unbounded formally normal operators}, journal = {Matematika}, pages = {117--135}, publisher = {mathdoc}, volume = {10}, number = {2}, year = {1966}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MAT_1966_10_2_a2/} }
G. Biriuk; E. A. Coddington. Normal extensions of unbounded formally normal operators. Matematika, Tome 10 (1966) no. 2, pp. 117-135. http://geodesic.mathdoc.fr/item/MAT_1966_10_2_a2/