"Vehículos espaciales." . . "Airplanes History." . . "Smithsonian Institution." . . "Rockets (Aeronautics)" . . . . . "Doctor Langley's paradox : Two letters suggesting the developement of rockets" . "Doctor Langley's Paradox : two letters suggesting the development of rockets" . "History" . "History"@en . . . . . . . . . . "Doctor Langley's paradox : two letters suggesting the development of rockets" . "Doctor Langley's Paradox: two letters suggesting the development of rockets, etc. [With plates, including portraits.]"@en . . "Doctor Langley's paradox" . . . . . . "Doctor Langley's paradox two letters suggesting the development of rockets"@en . . . "Doctor Langley's paradox: two letters suggesting the development of rockets" . "Doctor Langley's paradox : two letters suggesting the development of rockets (with three plates)" . "Doctor Langley's Paradox : Two letters suggesting the development of rockets. <With three plates>" . . . . . . . . . . "Doctor Langley's paradox two letters suggesting the development of rockets (with three plates)"@en . . . "Airplanes." . .