Wikimedia
Wikipedia: Refrain
Wikipedia article about the poetic device and musical term called refrain. It mentions a number of forms that use refrain as well as giving some examples from poems and songs.
Wikimedia
Wikipedia: Caesura
Encyclopedia article that defines and gives many examples of Caesura in poetry. Examples are taken from Latin, Old English, and Middle English poetry. Also defines different forms of Caesura (such as masculine caesura and feminine caesura).
Rutgers University
Rutgers University: Glossary of Literary and Rhetorical Terms
This is a glossary of literary and rhetorical terms in alphabetical order by Jack Lynch, Rutgers University. Click the desired link to find the definition.