710:50-3-38 Nonresidents; who must file

(a) A nonresident is required to file an Oklahoma Income Tax Return Form 511NR if $1,000.00 of gross receipts is from Oklahoma sources. (b) A return is required to establish a loss year, even though gross receipts may be less than $1,000.00. (c) Employees of interstate carriers (including railroads) are only subject to state income tax of the state of residence of said employee. [ See: 49 U.S.C.A. §§ 11502 and 14503]