@misc{Cayley_Arthur_(1821–1895)_On_1889, author={Cayley Arthur (1821–1895)}, copyright={Public Domain}, address={Cambridge}, journal={Mathematical papers}, howpublished={online}, year={1889}, publisher={Cambridge University Press}, language={eng}, title={On the Triadic Arrangements of Seven and Fifteen Things}, type={Text}, URL={http://rcin.org.pl/Content/119116/PDF/WA35_143407_12807-1_Art82.pdf}, }