Also note that Library Search actually searches for books and journal articles simultaneously, unless you narrow your search to only books, via the menu options on the left side of the screen.
L -- Education (General)
LA -- History of education
LB -- Theory and practice of education
LC -- Special aspects of education
LD -- Individual institutions - United States
LE -- Individual institutions - America (except United States)
LF -- Individual institutions - Europe
LG -- Individual institutions - Asia, Africa, Indian Ocean islands, Australia, New Zealand, Pacific islands
LH -- College and school magazines and papers
LJ -- Student fraternities and societies, United States
LT -- Textbooks
Dissertations may appear in your results in databases like ERIC or Education Source, but you won't be able to access their full text directly. They also won't always appear in results from the main Rowan search box.
Instead, search for dissertations in this database, which has PDF copies of nearly every dissertation submitted since 1997: