Glass collecting enthusiasts can look up glassware manufacturer marks online at websites such as 20thCenturyGlass.com and GlassLoversGlassDatabase.com. They may also identify manufacturer marks through print resources such as "The Encyclopedia of Glass: Revised and Expanded 2nd Edition."
20thCenturyGlass.com displays many photos of antique glassware manufacturer marks from numerous European regions, including Italy, Scandinavia, England, Ireland and Malta. Each image is accompanied by a history of the mark, a background on the manufacturer and his most popular pieces, and a gallery of the types of glassware on which it is found.
The Glass Lovers Database is managed and maintained by a group of glass collectors, sellers, authors and researchers. It has an extensive gallery of marks from manufacturers around the world. It also has separate databases of both the manufacturers and patterns used in glass making. Mark images are available individually or in sheets of commonly associated marks. Maker and pattern databases provide extensive information on manufacturers along with image galleries of their glassware.
Some collectors claim that a physical book is the still the easiest and quickest way to look up glassware marks. "The Encyclopedia of Glass" has over 4,200 entries on glassware patterns and motifs, as well as noted artisans, companies and designers.