Dathe, S. and Hendricks, W. 2007. The Nemesis E-Learning 4-Secotrs-Model - A Concept to Enhance the Reusability of E-Learning Products. International Journal of Emerging Technologies in Learning (iJET). 2, 2 (May 2007). DOI:https://doi.org/10.3991/ijet.v2i2.103.