1. Bond, D.C. and Holbrook, O.C.; Patent No.2,866,507, Gas drive oil recovery process (1958).
2. Jacobs, W.L. and Bernard, G.G.; U.S. Patent No.3,330,346 (1965).
3. Craig, F.F., Jr. and Lummus, J.L.; U.S. Patent No.3, 185,634 (1965).
4. Albrecht, R.A. and Marsden, S.S., Jr.; Soc. Pet. Eng. J., IP, 51-55 (1970).
5. Bernard, G.G. and Holm, L.W.; Soc. Pet. Eng. J., 10, 9–16 (1970).