Space weapons : a handbook of military astronautics / ed. by James H. Straubel ... [et al.] Sternenkriege" : Illusionen und Gefahren report on unidentified flying objects / E.J. Ruppelt Vliegende schotels in actie / Harold T. Wilkins ; geautoriseerde vertaling [uit het Engels] André E. Steentjes Soviet Militairy Space Doctrine Inside the space ships / by George Adamski ; foreword by Desmond Leslie Flying saucers / Donald H. Menzel Behind the flying saucers / F. Scully Vliegende schotels slaan ons gade / door Donald E. Keyhoe ; [vert. uit het Engels door André E. Steentjes] case for the UFO : unidentified flying objects / M.K. Jessup defense space interests Hearings before the committee on science and astronautic U.S. House of Representatives 87th congress, 1st Session, 17 - 23 march 1961