Hi there, I hope I've posted this in the right place. I have a question regarding including historical information in a piece of non-fiction. When is it necessary to reference where it's come from, and when isn't it? For example I've read (popular) travelogues where the writers have given an account of their journeys and experiences, but at the same time clearly done research on the places visited and given details about their history, without saying a word about where they learnt that information. Does it come down to how skilled the writer is at rewording what they've read to pass it off as their own knowledge? Many thanks for your advice.