Reddit mentions of PHR / SPHR Exam Study Guide 2016: Test Prep for the PHR/SPHR Professional in Human Resources Certification Exam (Trivium Test Prep)

I took the exam last spring and used three different books.

PHR/SPHR for Dummies - I did not use this as much as I used the books listed below.

PHR/SPHR Exam Study Guide 2016 - This was more of a summary of the areas covered. I got some good information out of it and it was a quick read.

PHR/SPHR Professional in Human Resources Certification Deluxe Study Guide - This was the most thorough of the books I purchased and I'm confident I can use it for PHR exam too, without having to worry about buying additional study materials.

I don't remember too much about the exam, but I wish you the best of luck!

*Note: I made flashcards off of information from the books and used those to study, once I finished reading the books.