Centennial, Phila'da. Pa., exposition postmark on 5 covers; first type (Bomar P76-01) tying 3¢ Banknote on two covers, each with different cork duplex, a third with quartered cork duplex tying 6¢ Banknote on purple 1776-International Exhibition, Philadelphia-1876/United States Centennial Commission. corner card cover (roughly opened at right), second type (Bomar P76-02) with cork duplex tying 3¢ Banknote on two covers, F.-V.F. Estimate  $200 - 300. $0 (Image)