His original papers are as accessible as popular press. The big ones are “Nature of the Firm” and “The Problem of Social Cost.” For the 2nd one, Coase complained it is used to reach the opposite conclusion than he intended.^

http://onlinelibrary.wiley.com/doi/10.1111/j.1468-0335.1937....

http://home.cerge-ei.cz/ortmann/UpcesCourse/Coase%20-%20The%...

^Essentially, Coase argues that in the absence of transaction costs, abcd. He meant this as a way of highlighting the importance of transaction costs, with abcd being obviously false in reality. Economists tend to assume efficient markets in their theory, so many read that statement to be boilerplate economist caveats.