2207.7 Pictorial, Graphic, and Sculptural Works
Acceptable methods for affixing and positioning the notice on a pictorial, graphic, or sculptural work include:
• Where a work is reproduced in two-dimensional copies, a notice is acceptable if it is affixed directly or by means of a label cemented, sewn, or otherwise attached durably, so as to withstand normal use, on the front or back of the copies, or to any backing, mounting, matting, framing, or other material to which the copies are durably attached, so as to withstand normal use, or in which they are permanently housed.
• Where a work is reproduced in three-dimensional copies, a notice is acceptable if it is affixed directly or by means of a label cemented, sewn, or otherwise attached durably, so as to withstand normal use, to any visible portion of the work, or to any base, mounting, framing, or other material on which the copies are durably attached, so as to withstand normal use, or in which they are permanently housed.
37 C.F.R. § 202.2 (C) (9) (I)-(ii).