A few books ~
To look for more ~
Search CBBcat for the SUBJECT Terrorism - History
Request books from Bates and Bowdoin by clicking in the line of buttons above the search boxes.
To find encyclopedia articles, go to Credo Reference (you can find it in CBBcat) and search "history of terrorism." You will get a long list of results; notice the title of the encyclopedia each article is published in (some are devoted to special topics) and the word count for the article (100 words is 3 or 4 sentences).