1. Fiorenza, R.; Pirelli, M.; Torella, E.; Kapus, P.; Kokalj, G.; Lebenbauer, M.: VVT+Port Deactivation Application on a Small Displacement SI 4 Cylinder 16V Engine: An Effective Way to Reduce Vehicle Fuel Consumption; SAE 2003-01-0020
2. Mischker, K.; Denger, D.: The Electro-Hydraulic Valvetrain System EHVS — System and Potenzial, SAE 2005-01-0774
3. Das Twinport System von Opel; Autozeitschrift mot, Ausgabe 10/2002
4. Opel Astra 1.6 Twinport Njoy; Autozeitschrift MOT, Ausgabe 10/2003
5. Fiorenza, R.; Pirelli, M.; Torella, Pallotti, P., E.; Kapus, P.; Praesent, B., Kokalj, G.; Pachernek, G.: Variable Swirl and internal EGR by VVT Application on small Displacement 2 Valve SI Engines: An Intelligent Technology Combination, Paper F2004V194, FISITA — World Automotive Congress in Barcelona “A new automotive culture for the 21st century”, 23. - 27. May 2004