APA (7th ed.) Citation

Willis, E. A., & Padrutt, J. A. (1969). Round trip trajectories with stopovers at both Mars and Venus. National Aeronautics and Space Administration.

Chicago Style (17th ed.) Citation

Willis, Edward A., and J. A. Padrutt. Round Trip Trajectories with Stopovers at Both Mars and Venus. [Washington, D.C.]: National Aeronautics and Space Administration, 1969.

MLA (9th ed.) Citation

Willis, Edward A., and J. A. Padrutt. Round Trip Trajectories with Stopovers at Both Mars and Venus. National Aeronautics and Space Administration, 1969.