which authors have you found so far? Turn to the literature you already know to explore this, and then expand – just as you would for a literature review, (which you probably have already done or will need too).
Have you looked at early critical ethnographers such as Jim Thomas? SAGE still has his work available. Have you looked at SAGE authors here on the methodspace such as Lisa Given 2008 encychlopedia? or maybe Victor Jupp 2006? Its hard work, but this is the work only you can do – best wishes