Here's a link to an older post I wrote on the importance of team building (particularized for Romania) and I paraphrased Graham Bell in the end of it, just as I had done here (in Romanian).
A very interesting recent report in Science, "The Increasing Dominance of Teams in Production of Knowledge" (subscription needed to view the full PDF), by three researchers from Northwestern University, makes the point above very clear for the specific area concerning production of scientific knowledge (in any discipline).
We have used 19.9 million papers over 5 decades and 2.1 million patents to demonstrate that teams increasingly dominate solo authors in the production of knowledge. Research is increasingly done in teams across virtually all fields. Teams typically produce more highly cited research than individuals do, and this advantage is increasing over time. Teams now also produce the exceptionally high impact research, even where that distinction was once the domain of solo authors. These results are detailed for the sciences and engineering, social sciences, arts and humanities, and patents, suggesting that the process of knowledge creation has fundamentally changed.
Stephen Dubner, on Freakonomics, touches on the same idea when explaining YouTube's success (though this is also about carefully selecting your team mates, previous succesful projects being priority sets...).