This is entirely boring, but absolutely necessary! All examination boards have policies about academic honesty and you risk your diploma if you submit any task to the IB that they think has been plagiarised. Remember that teachers / examiners (especially for History) are professionals and have been marking secondary school papers for a number of years. We know not only how to spot when the ‘voice’ of a paper changes but also how to find where it is from. Do not risk it! Acknowledge all ideas that come from external sources, except for what could be deemed common factual knowledge (eg WWII started in 1939. You should reference if a text suggests that WWII started in 1931).
Academic Writing: I give this out at the start of the year and tell my students not to lose it. Anything under 12pt font will be returned as ‘illegible’!
Harvard Referencing: A simple two page guide to Harvard in-text referencing. Use in conjunction with
Writing a Bibliography: A four page pamphlet that covers most scenarios for including in your Reference List.
And if you are totally stuck, Monash University’s 82 page Harvard Style Guide is here
Other universities’ style guides are also fairly easy to find, and will offer more advice than what can be fit onto only a couple of pages.