I'm reading through the 3rd edition of John G. Proakis Digital Signal Processing and I came across a possible errata in Figure 2.35c on page 116. I couldn't find any errata sheet on the publisher's or author's website. It appears to me that the "-a1" and "-a2" labels on the diagram on Figure 2.35c are swapped when compared to the difference equation shown for Equation 2.5.16. I don't have access to the latest 5th edition of the book but the labeling is unchanged in the 4th edition. I just want to make sure I'm not missing some nuance of the transformation from the "Direct form I structure" to the "Direct form II structure" version of the diagram. Thanks.