I hope someone, possible Oel, can help me with this spoon. It appears to be of an early Dutch style, but I have no records of any marks which might help to identify it. It is 19.8cm in length and weighs 60g.
I think if you go to the Hanau Germany section of the world marks on this site you will see that your spoon is a Hanau copy. The third mark is the only one I actually saw, but the other two are typical for Hanau. Maurice
I don't know of a book, you could find plenty of discussions by searching on this site under Hanau. Also this site has a two part article on the subject. I vaguely remember some articles in Silver Magazine. http://www.ascasonline.org/articolo13.html