The original papers on inclusive fitness theory are from W.D. Hamilton:
The first paper to carefully discuss reciprocal altruism is from Robert Trivers:
The Axelrod and Hamilton research turned into a much longer and very readable book which includes several chapters on political science and public policy recommendations as well as on the prisoner's dilemma and evolution. He also wrote a 'sequal' which is a collection of his papers.
Elliott Sober and David Sloan Wilson's Unto Others: The Evolution and Psychology of Unselfish Behavior discusses both biological and psychological altruism and the relationship between the two.
We read a longer version of Wilson and Wilson, but shorter, more popular pieces appeared as well:
In addition to the above two pieces and the longer piece we read, E. O. Wilson (and others) has a few other pieces arguing that kin-selection can't be the explanation of eusociality:
These papers have been entertainingly criticized by Richard Dawkinsa and Jerry Coyne in their respective blogs here: