Errata
 
Introduction to Languages and the Theory of Computation
John Martin, 3rd Edition

P. 366
There is an error in the delete example. In the diamond section of 
the diagram, the TM seems to have two transitions from state q_a on 
an 'a' and two from state q_b on a 'b', in fact these two inner arrows 
are just reversed. Thanks to Duncan for catching this.

P. 357
There is seemingly another error in Figure 9.23.
The bottom-most transition in the diagram seems to be bi-directional
(i.e. it points in both directions), but it should only point to the left.