Reference I've used

Collis, B. & Moonen, J. (2005). Flexible Learning in a digital world. London: Kogan Page Ltd.

Wade, W., Hodgkinson, K., Smith, A., & Arfield, J. (1994). Flexible Learning in Higher Education. London: Kogan Page Ltd.

Race, P., & Brown, S. (1993). 500 Tips for Tutors. London: Kogan Page ltd.