Coles, M. 1., Oates, T., & European Centre for the Development of Vocational Training. (2005). European reference levels for education and training: Promoting credit transfer and mutual trust : study commissioned to the Qualifications and Curriculum Authority, England. Luxembourg: Office for Official Publications of the European Communities.

Coles, Mike 1947-, Tim Oates, and European Centre for the Development of Vocational Training. European Reference Levels for Education and Training: Promoting Credit Transfer and Mutual Trust : Study Commissioned to the Qualifications and Curriculum Authority, England. Luxembourg: Office for Official Publications of the European Communities, 2005.

Coles, Mike 1947-, Tim Oates, and European Centre for the Development of Vocational Training. European Reference Levels for Education and Training: Promoting Credit Transfer and Mutual Trust : Study Commissioned to the Qualifications and Curriculum Authority, England. Luxembourg: Office for Official Publications of the European Communities, 2005.