Section 523 - Saving clause1. Any urban renewal program commenced or undertaken prior to the effective date of this article, in accordance with and pursuant to, any provision of the general municipal law, or other law in force immediately prior to the effective date of this article, shall in no manner be impaired or affected by the enactment of this article or the repeal of the applicable sections of the general municipal law. As to such urban renewal programs so commenced or undertaken, the provisions of any such law may be deemed continued thereunder until the completion of such program or programs. Nothing herein contained, however, shall prevent a municipality, having so commenced or undertaken an urban renewal program prior to the effective date of this article, from exercising any of the rights or powers granted in this article in conjunction with or substitution of the rights and powers of such municipality under any law in force immediately prior to the effective date of this article, until the completion of such program.2. Any provision in any law, rule, regulation, resolution, contract or other document relating to any right, power or duty of the state or of a municipality and which applied at the time the state or municipality exercised such power or right or performed such duty shall continue to apply notwithstanding any provision to the contrary of this article.3. An act of the legislature of the year nineteen hundred sixty-one which in form amends or repeals or purports to amend or repeal any provision or provisions of section seventy-two-k, seventy-two-l, seventy-two-m, seventy-two-n, or seventy-two-o of the general municipal law as in force at the time this act shall take effect shall be deemed and construed as an amendment or repeal, as the case may be, of the corresponding provision or provisions of such sections or law, as contained in this article.4. An act of the legislature of the year nineteen hundred sixty-one, which adds or purports to add a new section, subdivision or other provision of law to sections seventy-two-k, seventy-two-l, seventy-two-m, seventy-two-n or seventy-two-o of the general municipal law as in force at the time this act shall take effect shall be deemed and construed as having been added to this act and shall be given full effect according to its context as if the same had been added expressly and in terms to this act and shall be deemed and construed to have been inserted in this act in the appropriate position in regard to and as modifying the effect of the corresponding provision or provisions of this article.5. Reference in any general, special or local law, county, city or village charter or other special form of government, ordinance, resolution, rule, regulation or document or in any act of the legislature of the year nineteen hundred sixty-one to sections seventy-two-k, seventy-two-l, seventy-two-m, seventy-two-n or seventy-two-o of the general municipal law as in force at the time this act shall take effect shall be deemed and construed to refer to the corresponding provision of this article and shall be given full effect according to its terms as thereof specifically referring to such corresponding section or other provision of this article.