[by] R. W. Powell, C. Y. Ho, and P. E. Liley ; [Pt. 1], Pt. 2. -- U.S. Dept. of Commerce, National Bureau of Standards; for sale by the Superintendent of Documents, U.S. Govt. Print. Off., 1966-. -- (National standard reference data series NSRDS-NBS ; 8, 16,[etc.]).