To successfully complete this assignment you will need to find monographs--books and articles--that are not just about history, but that have been written by historians. This means you will need to do some additional research about the author (or sometimes authors) of the sources you find. You can also ask a librarian for help.
Many students need to borrow materials from libraries outside the RCC/JCLS system to complete this assignment, so it is very important that you begin your research several weeks before the paper is due.
It's not just historians who are interested in and writing about history: political scientists, economists, journalists, and nonfiction writers, to name a few, often write about historical subjects. But they don't write about them in the same way historians do. So was your monograph written by a historian? You may need to do some research before doing your research in order to figure it out.
-For books: check the back
If you have the book in hand (or your virtual hand, in the case of an eBook) you can check the author's biography. If it says she or he is, for example, a professor of history at "Big Name University" you have a book written by a historian. If it's a professor of any other discipline (Political Science, etc.) keep looking.
-For articles: check the author's contact information
Scholarly articles will generally include at least the name of the institution where the author was employed at the time of writing. The department may be included as well. Someone affiliated with the history department of a university can be assumed to be a historian. If there is no department mentioned, or if there is no college or university listed at all you will need to search for more information.
-Google the author(s):
If you don't have the book in hand or the author's information isn't there, try searching for their professional information. Are they associated with a university? What is their title? In what department do they teach? If the word "history" doesn't appear in either of those places you may need to keep looking. This can also be a reasonable place to use Wikipedia if your author is well-enough known to have a page there. Be absolutely certain you are looking at information for the correct person; even less common names are rarely totally unique.
Still not sure? Ask a librarian or and/or your professor. Make sure you include the title of the book or article, the author's name(s), and any other information you have found.