1) The second equation in the right column on p15 has the same expression left and right on the first line. There is no reason for this.
2) The equation in the left column on p21 includes $I_\theta$ in the integral after the bounds had already been specified on the integral. The $I_\theta$ is superfluous and possibly confusing.
Throughout the Measure of an Elf example, references to Runcor...