@misc{Sylvester_James_Joseph_(1814–1897)_On_1908, author={Sylvester, James Joseph (1814–1897)}, copyright={Public Domain}, address={Cambridge}, howpublished={online}, year={1908}, publisher={Cambridge University Press}, language={eng}, type={Text}, title={On the centre of gravity of a truncated triangular pyramid, and on the principles of barycentric perspective}, URL={http://rcin.org.pl/Content/115399/PDF/WA35_140182_11371-2_Art65.pdf}, }