"Understanding the Significance of the Number 220 in Numerology"1945-1972unknownhttp://rightsstatements.org/vocab/NKC/1.0/enghttp://congressarchives.org/record/CAC_CC_001_9_0000_1_6Shows major electric generation stations, co-op points, present and future OG&E and SPA lines. (April 15, 1949).