Complete Set of M.A. Armstrong trilogy (3) on U.S. Stamps, softbound,

black paperback copies in good used cond, (1) "U.S. Coil Issues 1906-38" has a few spots on back cover, name inscribed on title page, no marks or highlights on pages, (2) "Washington-Franklins 1908-1921" in good used cond w/no marks/highlights on pages, name inscribed on title page & minor creases at binding on front & back covers' (3) "U.S. Definitive Series 1922-1938" in very good used cond w/minor "ding" at btm of binding and a little highlighting. Great opportunity to obtain these "gold-standard" references