Yes, Granmaa posted two questions on Venetian cutlery similar to this spoon.
viewtopic.php?f=8&t=34461&p=89003&hilit=venetian#p89003
viewtopic.php?f=8&t=34543&p=107682&hili ... rk#p107682
Now, for some reason I don't know, the photos are very blurry, and perhaps Granmaa can post them again.
This spoon also has one of the many marks A and C separated by a castle, attributed to Anzolo Castelli, assayer between the end of the 17th and early 18th centuries.
As for the books on Venetian silverware, the most authoritative author is undoubtedly Piero Pazzi who has published several books on the subject.
It must be said, however, that as regards the images of the marks, these have all been reproduced on the book "Argenti italiani del settecento" by Donaver and Dabbene.
Best
Amena