Csikszentmihalyi Ph.D, Mihaly., Flow: The Psychology of Optimal Experience, Harper Perennial Modern Classics; 1st edition (July 1, 2008)
Al-Musyaiqih, Prof. Dr. Khalid bin 'Ali, Al-Mukhtashar fi Al-'Aqidah, Maktabah Ar-Rusyd, 1433 H.
Al Ghazali, Abu Hamid Muhammad, "An Exposition of the Hearts: Makashifat-ul-Quloob" (Ihya Ulm al-Dn), Scribe Digital (January 19, 2014)
Seligman, Martin Elias Pete, Authentic Happiness: Using the New Positive Psychology to Realize Your Potential for Lasting Fulfillment. New York: Free Press, 2004
Al-Jauziyah, Ibnu Qayyim, Ash-Shalah wa Hukmu Tarikiha, Dar Al-Imam Ahmad, 1426 H.