Convenience shops not exceeding 2,500 square feet of total floor area intended for the exclusive use of occupants of a planned residential development may be located within a multiple dwelling or an administration or community building for the development. Dwelling units may be located above shopping center or convenience shops. Business signs or displays shall not be visible from the outside of any such building. The following sales or services only are permitted within the aforementioned neighborhood shopping center or convenience shops; confections, delicatessens, drugs, dry goods, groceries, hardware, jewelry, laundromats, personal services and professional offices, dry cleaning and laundry pickup station.