The ornamental design for notebook paper, as shown and described.
FIG. 1 is a front elevation view of a first embodiment of notebook paper of conventional thickness showing our new design, the opposite side being the same or plain.
FIG. 2 is a front elevation view of a second embodiment of notebook paper of conventional thickness showing our new design, the opposite side being the same or plain.
FIG. 3 is a front elevation view of a third embodiment of notebook paper of conventional thickness showing our new design, the opposite side being the same or plain; and,
FIG. 4 is a front elevation view of a fourth embodiment of notebook paper of conventional thickness showing our new design, the opposite side being the same or plain.
The outside dashed line shown in the figures define the bounds of the notebook paper and form no part thereof.