Worlds in the sky : planetary discovery from earliest times through Voyager and Magellan / William Sheehan. Sheehan, William, 1954- Planets. Astronomy History. Planets Exploration. QB601 .S543 1992 523.2 20 SHE Includes bibliographical references (p. [223]-230) and index. Tucson : University of Arizona Press, c1992. c1992. 1992 Text xv, 243 p. : eng