Shepard, A., Taylor, F., & De Kay, D. (1985). Halley returns =: El retorno del cometa Halley. [Estados Unidos]: Lee Services Group.
Chicago Style CitationShepard, Alan, Frank Taylor, and Dennis De Kay. Halley Returns =: El Retorno Del Cometa Halley. [Estados Unidos]: Lee Services Group, 1985.
MLA CitationShepard, Alan, Frank Taylor, and Dennis De Kay. Halley Returns =: El Retorno Del Cometa Halley. [Estados Unidos]: Lee Services Group, 1985.
Warning: These citations may not always be 100% accurate.