An excellent resource concerning all things Morse code.
The English language edition of Morsum Magnificat, the Morse Magazine, otherwise known as “MM”, contained a vast amount of information and illustrations of interest to Morse operators, key collectors, historians, researchers and other Morse enthusiasts.
MM was first published in the Dutch language, by Morse enthusiasts, Rinus Hellemons PA0BFN, and Dick Kraayveld PA3ALM. They were later joined by Tony Smith G4FAI who helped them launch the English language edition of the magazine.
Published from 1986 to 2004, in 89 issues, with readers and contributors around the world, it covered every conceivable aspect of Morse telegraphy, past, present and future, in a truly international way.
Issues are available at the Internet Archive here.