1. Mendling, J., & Weidlich, M. (2012). Business process model and notation 4th international workshop. In Proceedings. Lecture notes in business information processing (p. 1). BPMN 2012, Vienna, Austria, September 12–13, 2012. Berlin: Springer.
2. Perinforma, A. P. C. (2015). The essence of organisation. Leidschendam: Sapio Enterprise Engineering.
3. Parnas, D. L., Hoffman, D. M., & Weiss, D. M. (2001). Software fundamentals. In D. L. Parnas (Ed.), Collected papers (xxiv, 664 p.). Boston: Addison-Wesley.
4. Dijkstra, E. W. (1970). Notes on structures programming.
5. Dijkstra, E. W. (1976). A discipline of programming (XVII, 217 p.). Prentice-Hall series in automatic computation. Englewood Cliffs, NJ: Prentice-Hall.