(EN) Constantine Rudyard Jurgėla, History of the Lithuanian Nation, Lithuanian Cultural Institute, Historical Research Sect., 1948, p. 92. URL consultato il 19 gennaio 2022 (archiviato il 19 gennaio 2022).
«The Teutons were by that time convinced of their inability to conquer Lithuania in one great crusade, and they changed their tactics into a Kleinkrieg. Since then, small German detachments made frequent sudden incursions»