A citation or reference must contain enough information for your reader to be able to locate the source for themselves.
This information about your source is called bibliographic information or bibliographic data.
Think WHO, WHEN, WHAT, WHERE.
1) WHO created the source
2) WHEN the source was created
3) WHAT the source is called
4) WHERE the source was created
TIP - You need to note down the bibliographic data for your source so that you can write an accurate citation. This is best done at the time you are researching, rather than when you are writing your assignment.
You can usually locate all of the bibliographic detail you need to create a citation from the source itself. However, if you have already returned your library book, or are having trouble locating all of the bibliographic data, a library catalogue record will also show you all of the information you need.