§ 36-55.1. through 36-55.6. These sections as set forth in Chapter 501 of the Acts of 1960, as amended by Chapter 303 of the Acts of 1973 and Chapter 95 of the Acts of 1975, relating to redevelopment and urban renewal authorities in counties having a density of population in excess of 4,000 per square mile, are incorporated in this Code by this reference.