- LOBACHEVSKY, NIKOLAI IVANOVICH: An entry from Macmillan Reference USA's <i>Encyclopedia of Russian History</i> by ALEXANDER VUCINICH, 2004
- Nikolai Ivanovich Lobachevsky: An entry from Gale's <i>Science and Its Times</i> by Sherri Chasin Calvo, 2000
- GEOMETRICAL RESEARCHES ON THE THEORY OF PARALLELS. TRANSLATED FROM THE ORIGINAL BY GEORGE BRUCE HALSTEAD. by Nikolai Ivanovich Lobachevsky., 1891
- Nikolai Lobachevsky: Russia, Mathematician, Nizhny Novgorod, Kazan Gymnasium, Johann Christian Martin Bartels, Carl Friedrich Gauss, Master's Degree, Physics
- CONVENTIONALISM: An entry from Gale's <i>Encyclopedia of Philosophy</i> by Carl Hoefer, 2006
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