Blue Rider Publishing

year of pub­li­ca­ti­onISBNauthor(s)title
1999978-1-902851-00-6Richard HumberstoneEstonian Air Force, 1918-40 (Insignia Air Force Special S.)
  ''978-1-902851-01-3Richard HumberstoneLithuanian Air Force, 1918-40 (Insignia Air Force Special S.)
2000978-1-902851-04-4   ''Latvian Air Force, 1918-40 (Insignia Air Force Special S.)