The images shown here are scanned from the National Archives microfilm publication M924, Historical Files of the American Expeditionary Force, North Russia, 1918 – 1919. The original records are located in Record Group 120, Records of the American Expeditionary Force (World War I), in the National Archives at College Park – Archives II (College Park, Maryland).
The descriptive pamphlet for M924, published by NARA, may be viewed or downloaded here.