Das Erbe Brentanos. Akten der Konferenz. "The Legacy of Brentano" in Kraków, Softcover, 312 Seiten
The distinction between content and object (COD, for brevity) of presentations and other mental phenomena is a very characteristic feature of brentanism.
Twardowski is a central figure in the development of this idea. However, not every philosopher, even from the Brentano school, considered the matters this way.
(Introduction: Jan Wolenski)