This is an article written by Juan-Fernando Duque-Osorio about the possible development of space settlements. The link below takes you to an English translation of the article and there is a also a link to the original. I was very flattered by the references to a film a friend and I have made about the Island One space colony and I think the article is an excellent description of the various possibilities.
https://docs.google.com/file/d/0B1jVURLdM68eSmdUUlVILVZyeXc/edit