@article{10_1017_S0017089599000178,
     author = {Kim, Mee-Kyoung and Ko, Eungil},
     title = {Square roots of hyponormaloperators},
     journal = {Glasgow mathematical journal},
     pages = {463--470},
     year = {1999},
     volume = {41},
     number = {3},
     doi = {10.1017/S0017089599000178},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089599000178/}
}