This topic has 0 replies, 1 voice, and was last updated 6 years, 6 months ago by Gary Williams. Author Posts 27 November 2015 at 17:19 #12305 There’s an paper by Adey here: http://eric.ed.gov/?id=ED442622 Shayer and Adey http://iopscience.iop.org/article/10.1088/0031-9120/23/2/005 APU: http://iopscience.iop.org/article/10.1088/0031-9120/23/6/304 http://www.kcl.ac.uk/sspp/departments/education/research/crestem/Researc… http://www.letsthink.org.uk/ Author Posts You must be logged in to reply to this topic.