Finite Difference Methods for Ordinary and Partial Differential Equations
In the algorithm at the bottom of p. 95, the definition of $\alpha_{k-1}$ should have $(z_{k-1}^T r_{k-1})$ in the numerator and the definition of $\beta_{k-1}$ should have $(z_{k-1}^T r_{k-1})$ in the denominator.
The last sentence of this page should then read "... and then use the $z$ vector in place of $r$ in several places in the algorithm."