AmericanAstronauticalSociety,the 21st AAS Goddard Memorial Symposium.Space applications at the crossroads (21st : 1983 : Maryland )：Proceedings of the 21st AAS Goddard Memorial Symposium ．V.55，science and technology series; a supplement to advances.AAS,10983.
Space applications at the crossroads (21st : 1983 : Maryland )：Proceedings of the 21st AAS Goddard Memorial Symposium ．V.55，science and technology series; a supplement to advances
AmericanAstronauticalSociety,the 21st AAS Goddard Memorial Symposium.AAS,10983.
