1. D. Goedhuis, “Reflections on the Evolution of Space Law,” p. 113, in Netherlands International Law Review 1966, issue 2.
2. H. A. Wassenbergh, Post War International Civil Aviation Policy and the Law of the Air, Nijhoff, The Hague, 1962, second revised edition.
3. Charles S. Murphy, then Chairman of the USCAB, before the International Aviation Club, Washington DC. November 16, 1967.