@richard_he Active 7 years ago ActivityProfileFriends 1Groups 13 View Base Name richard_he Institution LearningLab – Universität Duisburg – Essen Twitter richard_he Blog http://www.richard-heinen.de Slideshare https://de.slideshare.net/richard_he/ Share this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)