Close Primordial noble gases from Earth's mantle: Identification of a primitive volatile component,
Caffee, M. W., G. B. Hudson, C. Velsko, G. R. Huss, E. C. Alexander Jr., A. R. Chivas (1999),
Science, 285 p. 2115–2118,
10.1126/science.285.5436.2115.