In reply to
@chartgerink @katiecorker @JeffSpies @Metadata2020 @opencitations Hi. Slight clarification. @CrossrefOrg considers CR bibliographic metadata to be “facts” so not subject to copyright or CC-0. Other CR metadata (e.g. event data) is explicitly CC-0 or conferment w Open Definition https://opendefinition.org/od/2.1/en/