Rental housing mortgage insurance, housing the elderly mortgage insurance, nursing homes mortgage insurance, administrative regulations under sec. 207, 231 and 232 of National housing act, as amended, title 24, chap. 11, subchap. D, pts. 232, 233, 235-238, Code of Federal regulations, effective dates, sec. 207, Aug. 13, 1954, sec. 231, Sept. 23, 1959, sec. 232, when issued.