In recent video, today Matt Cutts explained that Google does not like the idea of stitching contents, content stitching basically is to copy the snippets of contents from various sources and re-present it as once piece of content posted on your own website.
Matt said that even if you provide link back to original sources of copied contents, even than Google does not like those type of content stitching and denied that it can lead rankings in Google search results. Instead of content stitching, its better to have overview written yourself which does not seems copied; Matt gave example of Wikipedia as Good example about how to summarize contents adding more details for creating your own page from different sources.
As per Matt, simply avoid copying contents from other sources and displaying them within quotes, it does not going to rank or help you to rank in Google search results.
So next time when you try to create contents, make sure you do not doing content stitching, just try to make it useful and unique adding value to users and readers.