These databases specialize in locating articles in scholarly/academic journals and related sources.

For these three databases, "lincoln abraham" probably is the basic search statement, to which other terms can be added.  For example, here is the result of a search in the America: History and Life database for materials on Lincoln and statesmanship, with "leadership" and "diplomacy" as possible synonymous terms for "statesmanship":

• "lincoln abraham" AND (statesman* OR leader* OR diploma*)

Please note the option to limit search results to "academic journals,"  to the lower-left of the results list.

To search the JSTOR database, use this variation of the above search (using a different form of Lincoln's name):

• "abraham lincoln" AND (statesman* OR leader* OR diploma*)

One of the methods one can use to determine if a book can be considered "scholarly" is to check reviews of the book in published sources, particularly in journal articles.   You can use any of the databases above on this page to find review, creating a search

• for the title of the book or
• some combination of the author's name and the book title.

Take this example of a book in our collection:  Lincoln and the Abolitionists by Fred Kaplan.  

A search of the Academic Search Complete database for the terms kaplan AND "lincoln and the abolitionists"  yields six book reviews.
One of the six reviews is from an academic journal, which might indicate that the book is considered "scholarly."  Of course, what the reviewers actually said about the book is important, too.