N.J. Stat. § 19:15-20
If a person shall be challenged as not qualified or entitled to vote, and the person challenging him shall specify a ground for such challenge to be that the person so challenged is an alien, the judge of election may forthwith tender to him an oath or affirmation, in the following form: "You do swear (or affirm, as the case may be), that to the best of your knowledge, information and belief, you were born a citizen of the United States, and that you do not owe allegiance to any foreign prince, potentate, state or sovereignty", and if the person so challenged shall refuse to take the oath or affirmation so tendered to him, he shall be deemed to be an alien, unless he shall produce at the time of claiming his vote, to the board, a lawful certificate, issued out of and under the seal of some court of record, having authority to admit aliens to the rights of a citizen of the United States, showing that he has been admitted to the rights of a citizen of the United States. In this case the judge shall tender to the person so challenged an oath or affirmation in the following form:
"You do swear (or affirm, as the case may be), that you are the person named in the certificate of naturalization which you have produced to the board." In case the person producing the same shall claim to have derived the rights of such citizen through the naturalization of his parent, such certificate shall show that the person alleged to be such parent has been admitted to the rights of such citizen. In this event, an oath or affirmation, in the following form, shall be tendered to such person:
"You do swear (or affirm, as the case may be), that to the best of your knowledge, information and belief, the person named in the certificate of naturalization which you have produced to this board was your parent, and that you were at the time of the naturalization of your parent under the age of twenty-one years, and resident of the United States." If the person so challenged shall in either case refuse to take the oath or affirmation so tendered to him, he shall be deemed to be an alien.
N.J.S. § 19:15-20