Classroom observation: it’s harder than you think
Professor Robert Coe
The influence of video analysis on the process of teacher change
Tonya R. Tripp and Peter J. Rich, Teaching and Teacher Education 28 (2012) 728-739
http://sites.uci.edu/bsemdpedagogyposts/files/2014/02/Tripp-T-Rich-PJ-2012.pdf