Greg Martin, Jonathan Bloom, Dan Saracino. Three Proper Subgroups Covering a Group: 10911. The American Mathematical Monthly, 110(8):743-744, 2003. [doi]
@article{MartinBS03,
title = {Three Proper Subgroups Covering a Group: 10911},
author = {Greg Martin and Jonathan Bloom and Dan Saracino},
year = {2003},
url = {http://www.jstor.org/stable/3647866},
researchr = {https://researchr.org/publication/MartinBS03},
cites = {0},
citedby = {0},
journal = {The American Mathematical Monthly},
volume = {110},
number = {8},
pages = {743-744},
}