@article{10_4153_CMB_1998_016_4,
     author = {So, Wasin},
     title = {An {Explicit} {Criterion} for the {Convexity} of {Quaternionic} {Numerical} {Range}},
     journal = {Canadian mathematical bulletin},
     pages = {105--108},
     year = {1998},
     volume = {41},
     number = {1},
     doi = {10.4153/CMB-1998-016-4},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1998-016-4/}
}