Keeping track of sources of information in reports and lab books as you use them has several advantages, not least that you're less likely to lose that all important document and won't spend two hours the morning before a deadline fabricating your references. Your reports may include a bibliography, but they should always include a list of numbered references.
Anything that you had to look up, or that isn't your original work should be referenced. Anything that your reader might not know should also be referenced.
For more details on referencing, see section 4 of the level 1 guide.
Referencing consists of two parts: a list of numbered references at the end of your report, and a pointer in the text.
For example, Young and Freedman might have the number  in your list, in which case you would place a  at the end of any sentence that uses information from Young and Freedman. Remember that equations are part of a sentence too, so place the reference at the end of the relevant sentence rather than by the equation.
The aim is to be able to uniquely identify any article regardless of source - reliable website, journal article, textbook page. Questions you should be able to answer just by looking at the references are: "Who said what? Published? By whom? Where? When? " Below is a list of information you should include to uniquely identify some types of sources.
Example: (1) Chen, L. et al., "Migration and Redistribution of Oxygen Vacancy in Barium Titanate Ceramics.", Applied Physics Letters, Aug. 14, 2006, Vol. 89, No. 7, Letter 071916.
Example: (2) Katz, J.,Race Car Aerodynamics: Designing for Speed, 2nd ed Cambridge, MA: Bentley, 2006, 4
Example: (3) History of PCB Manufacturing in Anniston, 2000. Solutia http://www.solutia.com/pages/anniston/pcbhistory.asp As of Sept 2006.
For proceedings published as a book, reference as a book.
Example: (4) G. J. Ashwell, A. P. Kuczynski and M. Szablewski,Proceedings of the NATO-ASI Conference on Low-Dimensional Materials and Device Material ed. R. M. Metzger (Plenum Press, New York, 1990).
Example: (5) Dirac P. A. M.The Quantum Theory of the Electron, Proc. Roy. Soc. (1928), A117 (610)
Example references (1) - (3) copied from Tipler, P.A., Mosca, G, Physics for Scientists and Engineers with Modern Physics, 6th ed. New York: W.H. Freeman and Company (2008) pp. 448, 828.
A plethora of solutions making referencing easy are available, and there are an even more ways of presenting references in a report. You may be using Microsoft Word whilst writing your report; it includes a referencing tool you can use to store references which can be re-used several time throughout your course without having to type them out more than once. It will also put in numbered (2) or named references (Katz, 2006) in your text, and update these numbers and names as you update your list of references.
If you use Latex, a package called Bibtex (available on ITS Vega and as part of the Miktex package on ITS Windows) can be used.