What about ODTs? Are they grey?

« The term of grey literature is sometimes applied for older material and special collections, especially in the field of digitization projects of scientific heritage. The following paper will analyse this term of “grey scientific heritage” and, based on empirical and conceptual elements, contribute to a better understanding of grey literature. Special attention will be paid on older theses and dissertations (OTDs), as a main part of scientific heritage especially from universities. (…) »