Miller's Encyclopedia of World Silver Marks by Judith Miller, is not a good reference work and is unfortunately full of errors. The marks of Zwolle are also not described correctly.
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Again the town mark of Zwolle is based on the coat of arms. Town mark Zwolle crowned for 1st standard or “grote keur” 934/1000 and town mark without crown, 3rd standard silver 833/1000 fineness. Town mark with R.D short for ‘Rijks Daalder’ (coinsilver) 892/1000 fineness, 2nd standard.
As far as I know there are no reference books about Dutch guild silver in English. Regarding city hallmarks and the corresponding year letters, the book
Goud en zilver merken van Voet, L. B. Gans Premsela & Hamburger is a must have. In the book no master marks are shown regarding the silver guilds in the various Dutch cities.
https://www.google.com/search?sca_esv=2 ... sid=mosaic
Here you can find more relevant information;
viewtopic.php?t=32028
Peter.