COLOMBIA, 1921, "30c" on 50c Pale Green, Air Post Surcharge (Colomphil 12; Scott C22b).
Tied to small piece with violet Bogota SCADTA handstamp, trace of National 3c at left, well-centered though overall toning, still Fine and rare, only a few examples thought to exist,
Fletcher notes one known but never seen one offered and Cruz-Bortfeldt shows three examples (not including the one offered here)
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