@article{10_1017_S0017089500005280,
     author = {Au-Yeung, Yik-Hoi and Ng, Kam-Chuen},
     title = {A remark on a conjecture of {Marcus} on the generalized numerical range},
     journal = {Glasgow mathematical journal},
     pages = {191--194},
     year = {1983},
     volume = {24},
     number = {2},
     doi = {10.1017/S0017089500005280},
     url = {http://geodesic.mathdoc.fr/articles/10.1017/S0017089500005280/}
}