Institut istorii estestvoznanii︠a︡ i tekhniki (Akademii︠a︡ nauk SSSR), International Astronautical Congress (18th 1967 Belgrade), V. N. Sokolʹskiĭ, Frederick C. Durant, Sovetskoe nat︠s︡ionalʹnoe obʺedinenie istorikov estestvoznanii︠a︡ i tekhniki