N.Y. Yonkers Income Tax Surcharge Law § 15-121
Withholding of the City of Yonkers earnings tax on nonresidents' wages shall commence on November 1, 1984. With respect to payment of wages made on or after November 1, 1984, the provisions contained in Part V of Article 22 of the New York State Tax Law relating to withholding of tax on wages shall be applicable with the same force and effect as if those provisions had been incorporated in full in this section and had expressly referred to the tax imposed by this article, except where inconsistent with the provisions of this article, except that the term "aggregate amount" contained in Subdivision (a)(1), (2), (3) and (4) of § 674 of the Tax Law shall mean the aggregate of the aggregate amounts of New York State personal income tax, city earnings tax on nonresidents authorized pursuant to Article 2-E of the General City Law or Article 30-B of the New York State Tax Law, city personal income tax on residents authorized pursuant to Article 30 of the New York State Tax Law or city income tax surcharge authorized pursuant to Article 30-A of the New York State Tax Law required to be deducted and withheld.
N.Y. Yonkers Income Tax Surcharge § 15-121