- Macaulay Co. (New York) (1)
- Maryland State Weather Service, in cooperation with the U.S. Weather Bureau (Baltimore) (1)
- McGill-Warner (St. Paul, Minn) (1)
- McGill-Warner Co (St. Paul, Minn), 1929 (1)
- McKinley Pub. Co (Philadelphia, Pa), 1929 (1)
- Michelin et Cie (Clermont-Ferrand, France) (1)
- Ministerie van Defensie Topografische Inrichting (Delft) (1)
