Historiography is very important in IB history, and really makes the difference between a 5 and a 6/7. The most simple way to incorperate historiography is to mention the school of historiography (e.g. Marxist) and if possible, the name of a historian who supports this view. It is VERY important however to make sure that historiography does not end up being a substitute for your own argument. The most sophisticated way of incorporating history is to mention what a historian/school of historiography argues and then go on to dispute that with evidence. This demonstrates that you are at the highest level, and that you are able to ENGAGE with the historiography rather than simply regurgitating it.