Nine circa 1980's commercial covers from various cities in SOUTH KOREA.  Covers came from various sources, and were sent to professors at OHIO STATE UNIVERSITY, COLUMBUS, OHIO. One envelope received perforated lettering upon arrival at OSU; I am not sure of this purpose.  There are NO ENVELOPE CONTENTS.  Mixed condition as usual; some faults are possible. Interesting postal history group for the specialist!  Study pictures carefully.