When reading work how can you tell or find out what type of historian the person is? e.g. marx , feminist etc?

I am writing a history personal study which is worth 30% of my overall grade for the year. My question is, "How significant was the role of Dr Sun Yat Sen in the Chinese Revolution of 1911?. I am doing quite a bit of research but about 60% of the marks are for interpretating different historians. Howcan you tell what school of history a historian is i.e. whether they are marxist, functionalist, socialist. historians I am using are Johnathon D. Spence. Mary Clabuagt Wright. Harold z. Schiffrin. Also how can you spot Internet sites and are they are useful or credible to a piece of original work.