@article{GDZPPN002348780, title = {On the Relation PQ -QP = -iI.}, journal = {Mathematica Scandinavica}, volume = {20}, year = {1967}, pages = {79-88}, zbl = {0149.10101}, url = {http://dml.mathdoc.fr/item/GDZPPN002348780} }
Fuglede, B. On the Relation PQ -QP = -iI.. Mathematica Scandinavica, Tome 20 (1967) pp. 79-88. http://gdmltest.u-ga.fr/item/GDZPPN002348780/