Explorateur de timbres ↺ Scott or Y & T ? Dr. Albert Schweitzer 1967 Regular and Airmail Stamps (April 20, 1967) Sc 559 / YT 567 Sc 560 / YT 568 Sc 561 / YT 569 Sc C273 / YT PA342 Sc C274 / YT PA343 Sc C275 / YT PA344 Sc C276 / YT PA345