Predating this is 'A Pattern Language', by Christopher Alexander. It seems that teams of < 8 are universally more productive, with ~5 being optimal (at least in Japanese Culture). 'A Pattern Language' is intriguing and useful because it uses real data, and sociological results, to deduce a theory, and makes specific suggestions for architecture and the usage of space. For example, it's suggested that people use converted homes for workspaces, due to the large variation in room size and privacy, and the presence of places to work, think, cook, eat, play, and relax. It also points out that smaller meetings and workspaces are more productive, and supports this by showing a graph of '% of people never to say anything' or 'ideas not expressed' versus participants in a meeting).