Business letter English / [by] H. O. Robertson [and] Vernal H. Carmichael. Robertson, Horace O., 1887- Carmichael, Vernal H., 1896- joint author. English language Grammar. English language Composition and exercises. Commercial correspondence. PE1115 .R55 1957 651.74 ROB New York: Gregg Pub. Division, 1949. 1949. 1957 Text x, 470 p. eng