@article {MATHEDUC.06428012,
author = {Northshield, Sam},
title = {Complex Descartes circle theorem.},
year = {2014},
journal = {American Mathematical Monthly},
volume = {121},
number = {10},
issn = {0002-9890},
pages = {927-931},
publisher = {Mathematical Association of America (MAA), Washington, DC},
doi = {10.4169/amer.math.monthly.121.10.927},
abstract = {Summary: We present a short proof of the Descartes circle theorem on the ``curvature-centers'' of four mutually tangent circles. Key to the proof is associating an octahedral configuration of spheres to four mutually tangent circles. We also prove an analog for spheres.},
msc2010 = {G75xx},
identifier = {2015d.00651},
}