Fibers & Cooperative Scheduling in Ruby - igvita.com
http://www.igvita.com/2009/05/13/fibers-cooperative-scheduling-in-ruby/
Ruby Fibers: 8 Useful Reads On Ruby’s New Concurrency Feature
http://www.rubyinside.com/ruby-fibers-8-useful-reads-on-rubys-new-concurrency-feature-1769.html