Crossref REST API

Crossref is the organisation behind most DOIs for scholarly publications. Its REST API gives metadata for more than 150 million journal articles, books, conference papers and datasets: titles, authors, journal, dates, references, licences and funders. Search works, look up a DOI, or browse by journal, publisher or funder. Responses are JSON. Free, no key needed; add your e-mail address to requests to use the faster 'polite' pool.