@article{01505612,
title = {The densest packing of 12 congruent circles in a circle.},
journal = {Beitr\"age zur Algebra und Geometrie},
volume = {41},
year = {2000},
pages = {401-409},
zbl = {0974.52015},
language = {en},
url = {http://dml.mathdoc.fr/item/01505612}
}
Fodor, Ferenc. The densest packing of 12 congruent circles in a circle.. Beiträge zur Algebra und Geometrie, Tome 41 (2000) pp. 401-409. http://gdmltest.u-ga.fr/item/01505612/