John, Fritz. "Extremum problems with inequalities as subsidiary conditions". Studies and Essays Presented to R. Courant on his 60th Birthday, January 8, 1948, 187—204. Interscience Publishers, Inc., New York, N. Y., 1948. OCLC1871554MR30135
Rimon, Elon; Boyd, Stephen (1997). "Obstacle Collision Detection Using Best Ellipsoid Fit". Journal of Intelligent and Robotic Systems. 18 (2): 105–126. doi:10.1023/A:1007960531949. S2CID10505238.
Rimon, Elon; Boyd, Stephen (1997). "Obstacle Collision Detection Using Best Ellipsoid Fit". Journal of Intelligent and Robotic Systems. 18 (2): 105–126. doi:10.1023/A:1007960531949. S2CID10505238.
John, Fritz. "Extremum problems with inequalities as subsidiary conditions". Studies and Essays Presented to R. Courant on his 60th Birthday, January 8, 1948, 187—204. Interscience Publishers, Inc., New York, N. Y., 1948. OCLC1871554MR30135