Items not in distributable net income of a nonresident trust or estate

(a) In determining a nonresident trust or estate's Connecticut taxable income derived from or connected with sources within this state, there shall be added or subtracted, as the case may be, any other items of income, gain, loss or deduction of the trust or estate recognized for federal income tax purposes but not reflected in distributable net income as provided in § 12-713(a)-2 of this Part, to the extent such items are derived from or connected with Connecticut sources, as determined in accordance with the applicable regulations of Part II as in the case of a nonresident individual.