Pioneering Period

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Across
  1. 2. Counterfeit stamp
  2. 5. Printing defect
  3. 6. Used stamp mark
  4. 8. Follow-up to Penny Black
  5. 15. Scarce stamp
  6. 18. Stamp verification
  7. 19. Date stamp
  8. 21. Assemblage of stamps
  9. 22. Stamp value appreciation
  10. 23. Unperforated stamps
Down
  1. 1. Relating to mail
  2. 3. Stamp reference book
  3. 4. Stamp printing surface
  4. 7. Stamp storage book
  5. 9. Public display
  6. 10. Stamp printing method
  7. 11. Postal stationery
  8. 12. Stamp collection storage
  9. 13. Embedded design
  10. 14. First adhesive stamp
  11. 16. Rare stamp find
  12. 17. Scarce stamp
  13. 19. number Stamp identifier
  14. 20. Sample stamp
  15. 24. Stamp collector