Tolong jelaskan mengenai Sumber rujukan dari Barisan Barat Laut dalam bahasa melayu

David Glantz, Stumbling Colossus: The Red Army on the Eve of World War, University Press of Kansas, 1996, Appendix A: Red Army Order of Battle

Португальский Ричард Михайлович, Доманк Альберт Степанович, Коваленко Александр Петрович Маршал С. К. Тимошенко Marshal S.K. Timoshenko, chapter on his command of the Northwestern Front (in Russian)

A short information on North-Western front in Russian