Do you want to see if a Crossref DOI (typically assigned to publications) refers to DataCite DOIs (typically assigned to data)? Here you go: https://web.archive.org/web/20150121025249/http://api.labs.crossref.org/graph/doi/10.4319/lo.1997.42.1.0001 Conversely, do you want to see if a DataCite DOI refers to Crossref DOIs?
Geoffrey Bilder (Sun,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: