@article{10_4153_CJM_1988_059_5,
     author = {Wu, Pei Yuan},
     title = {Products of {Normal} {Operators}},
     journal = {Canadian journal of mathematics},
     pages = {1322--1330},
     year = {1988},
     volume = {40},
     number = {6},
     doi = {10.4153/CJM-1988-059-5},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1988-059-5/}
}