MONACO (1969) Hands holding wrenches. Trial color proof block of 4. ILO anniversary. Scott No 748, Yvert No 806.
AVAILABLE AT $25
TUNISIA (1957) Labor bourse*. Trial color proofs in strip of 5 with color codes in margin. Scott No 309, Yvert No 441.
AVAILABLE AT $60
FRANCE (1959) Palace of Industry & Technology*. Trial color proof in maroon. Scott No 923, Yvert No 1206. Not easy to find!
AVAILABLE AT $12