This attribute specifies whether or not the product is free, and by default it is not. An article that should always be freely accessible may be either simply free, indicated by a "yes" value, or Open Access, indicated by an "openaccess" value. Articles that are Open Access should also include an appropriately populated <licensestatement> element.

Defined in shared attribute group: "Article Attributes"

This attribute is required but has a default value of "no". The allowed values are "yes", "openaccess" and "no".

The DTD contains the following attribute definition (note that embedded links are to definitions within the DTD page of this guide):

                productfree              (yes | openaccess | no)  "no"