What is a poem comprised of quotations?

It could be a "found poem", which the literary equivalent of a collage.

http://www.poets.org/viewmedia.php/prmMID/5780 It could also be a cento which according to dictionary.com is "a piece of writing, esp. a poem, composed wholly of quotations from the works of other authors." http://dictionary.reference.com/browse/cento