A. W. F. Edwards. Seven-Set Venn Diagrams with Rotational and Polar Symmetry. Combinatorics, Probability & Computing, 7(2):149-152, 1998.
@article{Edwards98, title = {Seven-Set Venn Diagrams with Rotational and Polar Symmetry}, author = {A. W. F. Edwards}, year = {1998}, researchr = {https://researchr.org/publication/Edwards98}, cites = {0}, citedby = {0}, journal = {Combinatorics, Probability & Computing}, volume = {7}, number = {2}, pages = {149-152}, }