1. Gay,Archibald,U.S.Patent3,756,024MethodandApparatusforCoordinatingPropulsioninaSingleStageSpaceFlight, February23, 1962.
2. Nau,R.A.,AerospaceplanePropulsionSystem/VehicleIntegrationStudy,GeneralDynamics/Astronautics,ASD-TR-63-1069,San Diego, CA,Vols.1-161963.
3. Yi,A.C.andC.S.Hill,Single-Stage-to-OrbitVehicleConceptualDesignUsinganAirCollectionandEnrichment Propulsion System, NASACR 187157 June,1991.
4. Bond,W.H.andA.C.Yi,ProspectsforUtilizationofAirLiquefactionandEnrichmentSystem(ALES)PropulsioninFully ReusableLaunch Vehicles, AIAA/SAE/ASME/ASEE 29thJointPropulsionConference,June28-30,1993.