Quote From sneaks:
have you just started your lit review? if so then you'll probably find whole areas of research, maybe even in other disciplines that will be relevant - they may not be on the exact topic but you'll probably end up reviewing them, so I wouldn't worry.
I'd talk about the research from non-academic sources but just make you highlight why it may not be as rigourous etc. and methodological flaws.
I have done the main bulk of the literature review though haven't written it all up. I haven't really found the same area in other disciplines.