8David Gray, Mark Morgan. Modern apprentices in college: something old, something new[J]. Journal of Vocational Education and Training, 1998,50(2):277-290.
9David Gray,Mark Morgan. Modem apprenticeship:falling the skills gap? [J]. Journal of Vocational Education and Training, 1998,50(1): 123-134.
10National Apprenticeship Service (NAS). The basics: Levels [EB/OL]. http ://www.apprentice- ships.org.uk/Be-An-Apprentice/The-Basics.aspx, 2011-03-10.