… revenue stamps, stamp-postmarks, first-day covers, postal stationery (stamped paper), and the like, used or unused, …
Explanatory notes
… revenue stamps, stamp‑postmarks, first‑day covers, postal stationery (stamped paper), and the like, used or unused, … of all kinds , i.e., receipt stamps, registration stamps, circulation permit stamps, consular stamps, stamped revenue … stamp (or a set of postage stamps) postmarked with its date of issue, and “ maximum cards ”. The latter are cards …