There are some e-book collections that can be found under the "Primary Sources" tab. In most cases, those books would be considered primary sources, which is why they reside there instead of on the secondary source page.
Browsing the stacks in Morris Library can be extremely helpful when you are looking for additional sources for your research. Most books related to African history can be found on the 3rd floor of Morris Library and fall under the following Library of Congress classifications:
C, D History - General
DT History - Africa
JQ1870 - JQ3981 African politics
You can also "browse" the shelves virtually by searching by Call Number through DELCAT.