When using information from different resources, it is important to give credit to the author(s) by citing the resource.
A citation has to include sufficient information on the resource used to make it easy for others to find. Such information includes the author, title (of the book, of the chapter, of the article, of the journal, of the website), publication date, etc.
There are many citation styles available, but, due to the subject of this competition, we recommend the use of American Chemical Society style.
Here are some examples:
Le Couteur, P.; Burreson, J. Napoleon’s Buttons: How 17 Molecules Changed History; Putnam: New York, 2003; pp 32–47.
Chapter in a book
Almlof, J.; Gropen, O. Relativistic Effects in Chemistry. In Reviews in Computational Chemistry; Lipkowitz, K. B., Boyd, D. B., Eds.; VCH: New York, 1996; Vol. 8, pp 206–210.
Klingler, J. Influence of Pretreatment on Sodium Powder. Chem. Mater. 2005, 17, 2755–2768