References
- Gelbard , E. M. 1960 . Applications of spherical harmonics method to reactor problems , Technical Report WAPD-BT-20, Bettis Atomic Power Laboratory .
- Gelbard , E. M. 1968 . “ Spherical harmonics methods: PL and double-P L approximations ” . In Computing Methods in Reactor Physics , Edited by: Greenspan , H. , Kelber , C. N. and Okrent , D. New York : Gordon and Breach Science Publishers .