. . . . "Experiments in the principles of space travel" . "Experiments in the principles of space travel"@en . . "Juvenile works" . . . . . . . . "This book discusses basic laws of science underlying rocket research and development." . . . . "Simple experiments, using easily obtainable equipment, designed to explain the scientific laws pertaining to rocket research and space travel." . "Simple experiments, using easily obtainable equipment, designed to explain the scientific laws pertaining to rocket research and space travel."@en . . . .