Nothing herein contained shall be construed as repealing or affecting in any way the authority for the issuance of bonds under sections 13, 14, 15 and 16 of chapter 295, Laws of 1949, chapter 4, Laws of 1951, chapter 216, Laws of 1951, and chapter 170, Laws of 1953, nor shall it affect bonds heretofore or hereafter issued in accordance with said statutes.