@conference {5689, title = {Provisioning strong and weak OER: Requirements of open informational Ecosystems}, booktitle = {Open Education Global Conference 2015}, year = {2015}, address = {Banff, Alberta, Canada }, url = {https://www.researchgate.net/publication/280317907_Provisioning_strong_and_weak_OER_Requirements_of_open_informational_Ecosystems}, author = {Heinen, Richard and Michael Kerres and Ingo Blees and Rittberger, Marc} }