1. P.M. Selzer, W.M. Fairbank, and C.W.F. Everitt, “A superfluid plug for space”, Adv. Cryo. Eng. 16, 277 (1971).
2. U. Schotte, “He II phase separation with slits and porous plugs for space cryogenics”, Cryogenics 24, 536 (1984).
3. J.B. Hendricks, and G.R. Karr, “The liquid-vapor transition in porous plug operation”, Adv. Cryo. Eng. 31, 861 (1986). The 3 flow regions described in this reference are different.
4. M.J. DiPirro, F. Fash and D. McHugh, “Precision measurements on a porous plug for use in COBE”, Proc. 1983 Space Helium Dewar Conf., University of Alabama (Huntsville), 1984, p. 121.
5. M.J. DiPirro, D.C. McHugh, and J. Zahniser, “Phase separators for normal and superfluid helium”, Proc. 12th Int. Cryo. Eng. Conf., Southampton, UK, Butterworths (London), 1988, P.681; M.J. DiPirro and P. Kittel, “Superfluid helium orbital resupply: the status of the SHOOT flight experiment and preliminary user requirements”, Proc. SPIE 973, 44 (1988).