Editors. "USA invades Puerto Rico". The Literary Encyclopedia. First published 30 December 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=19263, accessed 18 April 2014.]
In the course of the Spanish-American War in the Caribbean, the USA now invades the Spanish colony of Puerto Rico. Before long Spain is calling for peace and agreeing to negotiate.