1. Report to the Congress of Matters Contained in the Helium Act (Public Law 86–777) Fiscal Year 1969 by The Secretary of the Interior
2. SEIBEL, C. W. Helium, Child of the Sun
3. Superconductivity inNb3Sn at High Current Density in a Magnetic Field of 88 kgauss
4. Federal helium Conservation Program, Heartings Before the Subcommittee on Mines and Mining of the Committee on Insular Affairs, House of Representatives, September 1969. See in particular the testimony of Harold W. Lipper; Chief, Division of Helium
5. ‘Review of the Government's program of supply current future helium requirements’, Report of the Comptroller General of the United States to Committee on Interior and Insular Affairs, House of Representatives (September 1969)