@article{01973835, title = {The densest packing of 13 congruent circles in a circle.}, journal = {Beitr\"age zur Algebra und Geometrie}, volume = {44}, year = {2003}, pages = {431-440}, zbl = {1039.52015}, language = {en}, url = {http://dml.mathdoc.fr/item/01973835} }
Fodor, Ferenc. The densest packing of 13 congruent circles in a circle.. Beiträge zur Algebra und Geometrie, Tome 44 (2003) pp. 431-440. http://gdmltest.u-ga.fr/item/01973835/