Lawrence Chung Julio Cesar Sampaio do Prado Leite On Non-Functional Requirements in Software Engineering. 363-379 2009 Conceptual Modeling: Foundations and Applications http://dx.doi.org/10.1007/978-3-642-02463-4_19 conf/birthday/2009mylopoulos db/conf/birthday/mylopoulos2009.html#ChungL09