1. S. R. Breon, Liquid helium servicing from the space station, 1987 Space Cryogenics Workshop, Madison, to be published in Cryogenics.
2. M. J. DiPirro and S. H. Castles, Superfluid helium flight demonstration using the thermomechanical effect, Cryogenics2fi: 84 (1986).
3. M. J. DiPirro and P. Kittel, The superfluid helium on orbit transfer flight demonstration, Paper No. DA-3, 1987 Cryogenic Engineering Conference.
4. P. Kittel, Losses in fountain effect pumps, Proc.11th International Cryogenic Engineering Conference, Butterworth, London, (1986) p. 317.
5. see for instance, J. Wilks, “The Properties of Liquid and Solid Helium”, Clarendon Press, Oxford, (1967).