If you mean Plutarch's Life of Pericles, that would be the main source (we don't have anything written by Pericles himself).

Other than Plutarch our sources are given in this article, under "Aspasia. 1." Other than Plutarch they're just isolated references -- passing remarks in Aristophanes, the Aristophanes scholia, Athenaios, Plato, Xenophon, etc. -- so none of them should be considered as a "major" source. Having said that, Aristophanes Plato and Xenophon do carry a lot more weight, since Plutarch is extremely unreliable for anything prior to 400 BCE or so.