Section 633 - New York source income of a nonresident estate or trust(a) General. The New York source income of a nonresident estate or trust shall be the sum of the following: (1) The net amount of items of income, gain, loss and deduction entering into federal adjusted gross income, as determined under paragraph four of subsection (e) of section six hundred one, derived from or connected with New York sources. Such determination of source shall be made in accordance with the applicable rules of section six hundred thirty-one as in the case of a nonresident individual.(2) The portion of the modifications described in section six hundred eighteen which relate to income derived from New York sources other than that portion of the modification provided in subsection three thereof which relates to section six hundred fifteen.(b) Special New York source rules. Deductions with respect to capital losses, passive activity losses and net operating losses shall be based solely on income, gains, losses and deductions derived from or connected with New York sources, under regulations of the tax commission, but otherwise determined in the same manner as the corresponding federal deductions.