Continuing their look at the upcoming R2 release, the GP team explains Microsoft Dynamics GP 2013 R2 Feature of the Day: Requisition Management Integration Points
Microsoft Dynamics GP 2013 R2 Feature of the Day: Requisition Management Integration Points – Inside Microsoft Dynamics GP
Tips & Hidden FeaturesDevelopment & IntegrationGP 2013
Archived post from 2014. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.