unmounted mint Block of Four 1967-70, the collection of blocks of four, including 1967 (23 May) Anniv. of Talks at the Yanan Forum 8f. (3), 1967 Long Live Chairman Mao 4f. to 52f., and 1968 Revolutionary Literature and Art both series 8f. (10). Mainly very fine unmounted mint. Cat. $2232