Credo Reference Credo Reference presents content from hundreds of reference books from some of the world's best reference publishers. Credo contains dictionaries, bilingual dictionaries, thesauri, subject encyclopedias, quotations and atlases, plus a wide range of subject-specific titles covering everything from art to accountancy to zoology, science to Shakespeare, and law to literature. There are over 3 million entries, 65,000+ images (art, diagrams, interactive maps and photos).