1. Chemical analysis of stratospheric samples from 50 and 70 km height;Chackett;J. Atmos. Terrest. Phys.,1950
2. Determination of tritium by mass spectrometric measurements of 3He;Clarke;Int. J. Appl. Radiat. Isot.,1976
3. Sorption of gases by ?active? charcoal, silicates (including glasses) and cellulose (revised by G. L. Gaines, Jr.);Dushman,1962
4. World natural gas: 1978;Energy Information Administration;Energy Data Report, U.S. Department of Energy, DOE/EIA-0133 (78),1980
5. Toward a method of quantitative separation of helium-neon mixtures;Ermolin;Trudy Radievogo Inst. im. V.G. Khlopina 6,1957