The ornamental design for a shelf for refrigerator, as shown and described.
FIG. 1 is a front perspective view of a shelf for refrigerator showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a cross-sectional view taken along the line 8-8 of FIG. 2;
FIG. 9 is an enlarged view of the encircled portion 9 in FIG. 8;
FIG. 10 is another front perspective view thereof depicting the drawer in an alternate position; and,
FIG. 11 is another front view thereof showing an example refrigerator in dashed broken lines to provide example environment.
The dashed broken lines in the drawings represent example environment and form no part of the claimed design. The dot-dash broken lines in the drawings encircle portions of the claimed design that are illustrated in enlargements and form no part of the claimed design.