I find Ivo's book really informative and have referred to it on numerous occasions. The only problem is the tiny writing. :cry:
I have just treated myself to Bill's book, for my birthday, so as yet I cannot comment on it as it has not arrived. :cry:
For Scandinavian glass, I can recommend Smoke & Ice or Fire & Sea, both by the same authors, Leslie Pina & Lorenzo Vigier, so count as one (to my reckoning anyhow). :wink: