1. Department of Online Learning and Instruction, Open Universiteit, Heerlen, The Netherlands
2. Education and Learning Sciences Group, Wageningen University and Research, Wageningen, The Netherlands
3. Educational Sciences Department, Faculty of Literature and Humanities, Urmia University, Urmia, Iran
4. School of Education, Calgary University, Calgary, Canada
5. Department of Educational Leadership, Policy and Technology Studies, The University of Alabama, Tuscaloosa, AL, USA