Hall, C. G., & Merkle, R. A. (1943). The sky's the limit!: Jobs in commercial aviation and how to get them. Funk & Wagnalls company.

Hall, Charles Gilbert, and Rudolph A. Merkle. The Sky's the Limit!: Jobs in Commercial Aviation and How to Get Them. New York , London: Funk & Wagnalls company, 1943.

Hall, Charles Gilbert, and Rudolph A. Merkle. The Sky's the Limit!: Jobs in Commercial Aviation and How to Get Them. Funk & Wagnalls company, 1943.