In the first two articles of this series devoted to Evidence-Based Medicine, we have shown how to translate a clinical problem in a well formulated question and how to derive search terms from the PICO. In this article, we describe in more detail the different sources of information and how to use them. The strategy will be illustrated by answering the question whether it should be recommended to treat hypercholesterolaemia in a young woman without cardiovascular risk factors. In a following article, we will show how to adapt a search strategy to a specific question or PICO.