Dyfyniad APA

ebrary, Inc, Greenberg, J. S., & Hertzfeld, H. (1992). Space economics. American Institute of Aeronautics and Astronautics.

Dyfyniad Arddull Chicago

ebrary, Inc, Joel S. Greenberg, and Henry Hertzfeld. Space Economics. Washington, D.C.: American Institute of Aeronautics and Astronautics, 1992.

Dyfyniad MLA

ebrary, Inc, et al. Space Economics. American Institute of Aeronautics and Astronautics, 1992.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.