CrossMark Policy Page

Crossmark is a multi-publisher initiative from Crossref to provide a standard way for readers to locate the current version of a piece of content. By applying the Crossmark logo Publisher Name is committing to maintaining the content it publishes and to alerting readers to changes if and when they occur.
Clicking on the Crossmark logo will tell you the current status of a document and may also give you additional publication record information about the document.