Start with high-confidence aquatic exercise books, then narrow by subgenre or adjacent topics.
Science of Swimming
Brett Hawke
Water Fitness Lesson Plans and Choreography
Christine Alexander
Your Water Workout
Dr. Jane Katz, Jane Katz
Get Wet, Get Fit
Megan Quann Jendrick, Nathan Jendrick
Make the Pool Your Gym
Dr. Karl Knopf, Karl Knopf
Cold Joy
Libby DeLana
Water Yoga
Christa Fairbrother