Brown et al., "Stimulation Treatment Selectivity Through Perforation Ball Sealer Technology", The Petroleum Engineer, 6-1959, 8 pages. |
Howard, "Ball Sealers in Fracturing and Acidizing", Canadian Oil and Gas Industries, Jan. 1962, pp. 43-46. |
Neill et al., "An Inexpensive Method of Multiple Fracturing", Drilling and Production Practice, American Petroleum Institute, 1958, N. Y., N. Y., pp. 27-32. |
Permeator Corp. (Canada) Ltd., "Permeator Well Completion Operator's Manual", Revised 9-1967, copyright 1964, pp. 30-33. |