@misc{Cayley_Arthur_(1821โ€“1895)_On_1889, author={Cayley Arthur (1821โ€“1895)}, copyright={Public Domain}, address={Cambridge}, journal={Mathematical papers}, howpublished={online}, year={1889}, publisher={Cambridge University Press}, language={eng}, type={Text}, title={On the Reduction of du รท โˆš U, when is a Function of the Fourth Order}, URL={http://www.rcin.org.pl/Content/119044/PDF/WA35_143208_12807-1_Art33.pdf}, }