@article{N 94-33533, note = {Distributed to depository libraries in microfiche.}, author = {DeVincenzi, Donald L. and Klein, Harold P. and Bagby, John R.}, url = {http://library.usi.edu/record/179473}, title = {Planetary protection issues and future Mars missions [microform] /}, publisher = {National Aeronautics and Space Administration, Ames Research Center ;}, number = {N 94-33533}, recid = {179473}, pages = {1 v.}, address = {Moffett Field, Calif. :}, year = {1991}, }