@article{10_4153_CJM_1968_135_8,
     author = {Brown, Arlen and Pearcy, Carl},
     title = {Operators of the form {PAQ-QAP}},
     journal = {Canadian journal of mathematics},
     pages = {1353--1361},
     year = {1968},
     volume = {20},
     number = {1},
     doi = {10.4153/CJM-1968-135-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1968-135-8/}
}