Another option to sample research topics is to browse issues of journals in the field. A few journals focused on 18th-century history are listed below:
Reference books cannot be checked, to ensure they are available for everybody to use. You may make copies of reference book entries, or scan/e-mail them to yourself, by using the library's printers. Or, if you need an extensive amount of information from a reference book, you may ask for permission to check it out for a limited period of time.