Periodic orbits / by F.R. Moulton, in collaboration with Daniel Buchanan, Thomas Buck, Frank L. Griffin, William R. Longley and William D. MacMillan. Moulton, Forest Ray, Griffin, Frank Loxley, Buchanan, Daniel. Buck, Thomas, 1881- Longley, William Raymond, 1880-1965. MacMillan, W. D. (William Duncan), 1871- Orbits. QB355 .M6 521.3 MOP Includes index. Washington : Carnegie Institution of Washington, c1920. c1920. 1920 Text xiii p, 524 p. : eng Carnegie Institution of Washington publication ;