An improved method for preparing gravimetric standard gas mixtures of helium-4 in nitrogen [microform] /
Bibawy, Nabil A.
Emerson, David E.
Washington, D.C. (2401 E St., N.W., MS #9800, Washington 20241) : U.S. Dept. of the Interior, Bureau of Mines,
1990.
Includes bibliographical references (p. 7).
Microfiche.
Gases.
Helium.
Nitrogen.