Forgeries of Mi 48-49 are very well done and are difficult to identify at first glance. However, there are a few small details from which forgeries of both values can be revealed:

1. A small appendix on the ornament under the number "8" in "1876"
2. Enlarged hook on the ornament to the left of the stamp

Forgery	Original

Serrane describes deviations in the faces in the upper corners of the stamps and asymmetric letters in "CTOT." The drawn illustrations in The Serrane Guide, however, match neither the descriptions in Billig's Handbook nor my own scans. This might indicate the existence of another set of forgeries of this issue.

Sources:
- Billig's grosses Handbuch der Faelschungen, Part 34, Vienna, 1937
- F. Serrane: The Serrane Guide, APS 1998
- R. Weinbrecht: Handbuch Bulgarien, Postwertzeichen Teil 1, 1879-1944, 1993