





Brown 1958 uses an outlined version of the key and slightly inclined letters.
FOTW attributes R401 to Brown 1926, but Rosanoski says that source should resemble R404. The Ships List displays both versions.
A three-coloured flag offered on German eBay has blue sans-serif initials instead of red. Its stated dimensions were approximately 117 by 201 cm. Jan Mertens relates the red, white and key to Bremen but could not explain the blue-letter variant.