Berle, A. K., & Camp, L. S. d. (1959). Inventions, patents, and their management. D. Van nostrand company.
Dyfyniad Arddull ChicagoBerle, Alf K., and L. Sprague de Camp. Inventions, Patents, and Their Management. London: D. Van nostrand company, 1959.
Dyfyniad MLABerle, Alf K., and L. Sprague de Camp. Inventions, Patents, and Their Management. D. Van nostrand company, 1959.
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