Okay, I've made the change as erratum 1. I divided the sentence into two because the antecedent of "which" wasn't completely clear:
Each invocation of the generator returns a new random source created by calling make-random-source (SRFI 27). The new random source is passed to random-source-pseudo-randomize! with i, and successive integers j (starting with 0), before being returned. Thanks, everyone.
