See full volumes online at library.ut.ac.ir/the-encyclopaedia-of-islam. The whole collection can be searched at referenceworks.brillonline.com, e.g. the keywords "Bahāʾī," "Bahā'ism," and "Bābism."

See also Glossary of Terms and Index (PDF, 15MB, offsite).

Searching this collection I saw these 40 articles of note; if you find something I missed, please let me know!