Gorilla Mindset is the result of my lifelong work on myself and countless others. Part of the work we put into ourselves includes reading a lot of books. Many of these books are useful for you.
Body of a Spartan (buy it here)
Becoming the Bull (Amzn)
30 Days of Discipline (buy it here)
Get Serious (Amzn)
NLP: The New Science of Human Achievement (Amzn)
The Millionaire Next Door (Amzn)
Choose Yourself (Amzn)
Love Yourself Like Your Life Depends on It (Amzn), which discusses the power of affirmations.