Competitive markets: how they work and why they fail
A few mistakes I've noticed for anyone who wants to use the notes to correct:
In the section on demand, I've put in the wrong formula for XED. It should be:
XED = %Change Quantity demanded of good b / %Change good A
Also, in the section on government intervention/failure on specific tax it should say that a tax shifts the MPC curve upwards, not leftwards. Also, the diagram shown is of a specific tax, if it was of an ad valorem tax then MPC + Tax would be the same as the MSC curve on the diagram.