Only one sheet of No. 13 was overprinted inverted, so any constant flaw on this sheet is unique...
1945 Mostar provisional issue, No. 13, 30 kn / 3.50 kn - Petar Zrinski with inverted overprint. Constant flaw Jugosiavija instead of Jugoslavija, overprint position 85, base stamp position 42. Ex Tiberio. Unique.
