cover 1956 (8 Mar.) airmail envelope registered to San Francisco bearing old currency $200 shepherdess used in combination with new currency Workers 8c. (4) and Tien An Men $1 tied by Harbin c.d.s. and showing the registration label at left, backstamped via Canton. Late use of mixed currency franking, shortly before the old currency stamps were invalidated

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cover 1956 (8 Mar.) airmail envelope registered to San Francisco bearing old currency $200 shepherdess used in combination with new currency Workers 8c. (4) and Tien An Men $1 tied by Harbin c.d.s. and showing the registration label at left, backstamped via Canton. Late use of mixed currency franking, shortly before the old currency stamps were invalidated