@article {MATHEDUC.06132026,
author = {Trenkler, G\"otz and Trenkler, Dietrich},
title = {The numerical range of the Luoshu is a piece of cake -- almost.},
year = {2012},
journal = {The College Mathematics Journal},
volume = {43},
number = {5},
issn = {0746-8342},
pages = {371-376},
publisher = {Mathematical Association of America (MAA), Washington, D.C.},
doi = {10.4169/college.math.j.43.5.371},
abstract = {Summary: The numerical range, easy to understand but often tedious to compute, provides useful information about a matrix. Here we describe the numerical range of a $3 \times 3$ magic square. Applying our results to one of the most famous of those squares, the Luoshu, it turns out that its numerical range is a piece of cake -- almost.},
msc2010 = {H65xx (G75xx)},
identifier = {2013a.00672},
}