The Getty Research Portal is an online search platform providing global access to digitized art history texts in the public domain. Through this multilingual, multicultural union catalog, scholars can search and download complete digital copies of publications (including rare books, foundational literatures, and periodicals) for the study of art, architecture, material culture, and related fields.
Try using one of the following specialized reference works to get started with your research. You can browse these to spark a paper topic or look up information about a term or technology cited elsewhere.
Scholarly encyclopedias are great, authoritative ways to understand more about a topic (and always better than Wikipedia, which is not an appropriate source for academic research), and they can give you information about where to look next. But remember that these are reference tools, and as such they are usually not appropriate sources for a scholarly paper on their own.