The sources report provides you with information about sources which bring you the majority of the traffic and quickly estimate the quality of that audience (by looking at the average page depth).
You can unfold any item to get the information about top performing articles from the source. The data can be obtained for any period of time, which you can select using the calendar at the top.
You can notice that numbers in "sources" filter of "Home" report aren't matching the numbers in "sources" report. It's caused by different counting algorithms: in the home report, you see the number of view in context of pages, while the actual report counts them basing on session's source.
Imagine the visitor comes from Google to the main website page, then opens a category, then reads an article. The sources filter in "Home" report will count +1 pageview to the following groups: search engines, main page, other pages. In a meantime, the "sources" report will count +3 pageviews to "Google".