@article{MV_1966_18_3_a10,
     author = {J. W. Moon and L. Moser},
     title = {An extremal problem in matrix theory},
     journal = {Matemati\v{c}ki vesnik},
     pages = {209 },
     year = {1966},
     volume = {18},
     number = {3},
     url = {http://geodesic.mathdoc.fr/item/MV_1966_18_3_a10/}
}