Creswell, J. W. (2013). Research design: Qualitative, quantitative, and mixed methods approaches. (4th ed.) 

Green, M., Iparraguirre, J., Davidson, S., Rossall, P., Ray, S. and Zaidi, A. (2017). A summary of Age UK's Index of Wellbeing in Later Life 

McNair, S. (2012). Older People's Learning in 2012: A Survey: NIACE

Wenger, E. (1998). Communities of practice : Learning, meaning, and identity. Cambridge: Cambridge University Press.