Hello everyone, I am in a bit of a rut. Helping one of my clients with a very intense lit search this afternoon, I have not been able to find a previous indexing term for "multicenter study" as a publication type. While searching the online MESH search engine from the NLM site, I found that it was introduced in 1991. I do not want to use the term "multicenter studies" as a MESH descriptor as described by this page from the Indexing Principles fro Category E (http://www.nlm.nih.gov/mesh/2K/indman/chapter_26.html#26.26.3), as they produce articles about the concept of the type of study. I am only interested in finding multicenter studies as a publication type prior to the term introduced into indexing in 1991. I know they exist, but need some other terms. The online and pring MESH does not give any previous terms. I have tried to limit by searching for the term this way: multicenter study [ti] or multicenter study [ab] and limiting by date Is this the way to go?? Can anyone offer any suggestions for me? Thanks, Holly ~~~~~~~~~~~~~~~~~~~~~~~~~~ Holly A. Harden Liaison Librarian Welch Medical Library Johns Hopkins University [log in to unmask] 410.502.7570 "Anyone who has not made a mistake has not tried anything new" --A.E.