About ERS ERS is the central resource office for Denver Public Schools. ERS provides five types of circulating libraries to DPS Schools; Classroom, Video/Multimedia, Art, Music and PE. ERS also provides technical support for DPS Library Media Centers and librarians utilizing the Via library automation system and LION (Library Information on the Net) - the library web catalog. We also assist with acquisition of materials for the library, development and maintenance of the collections, and help promote the relationship between libraries and student achievement at DPS. Click here to see a list of the departments within ERS.