Astronomical papers prepared for use of American ephemeris and nautical almanac: v. 11, pt. 3, Primary reference stars for Pluto, [by H. R. Morgan; v. 11, pt. 4, Rectangular coordinates of Ceres, Pallas, Juno, Vesta, 1920-60, by Paul Herget, G. M. Clemence, Hans G. Hertz].