@misc{Sylvester_James_Joseph_(1814–1897)_A_1904,
 author={Sylvester, James Joseph (1814–1897)},
 copyright={Public Domain},
 address={Cambridge},
 howpublished={online},
 year={1904},
 publisher={Cambridge University Press},
 language={eng},
 type={Text},
 title={A demonstration of the theorem that every homogeneous quadratic polynomial is reducible by real orthogonal substitutions to the form of a sum of positive and negative squares},
 URL={http://rcin.org.pl/impan/Content/114106/PDF/WA35_139239_11371-1_Art47.pdf},
}