The Little Engine That Could

제목: The Little Engine That Could 저자: Watty Piper  (Author), George Hauman (Illustrator), Doris Hauman (Illustrator) Grosset & Dunlap; Complete original ed edition (July 31, 2001)   https://www.amazon.com/Little-Engine-Could-Original-Classic/dp/0448405202/ref=sr_1_1?s=books&ie=UTF8&qid=1535378163&sr=1-1&keywords=piper+the+little+engine+that+could   

The Science of Optimism and Hope: Research Essays in Honor of Martin E.P. Seligman

제목: The Science of Optimism and Hope: Research Essays in Honor of Martin E.P. Seligman 저자:  Jane E. Gillham Templeton Foundation Pr (November 2000)   https://www.amazon.com/Science-Optimism-Hope-Research-P/dp/1890151262/ref=sr_1_1?s=books&ie=UTF8&qid=1535377554&sr=1-1&keywords=gillham+the+science+of+optimism+and+hope   

Well-Being: Foundations of Hedonic Psychology

제목: Well-Being: Foundations of Hedonic Psychology 저자: Daniel Kahneman, Edward Diener, Norbert Schwarz Russell Sage Foundation (February 13, 2003)   https://www.amazon.com/Well-Being-Foundations-Psychology-Daniel-Kahneman/dp/0871544237/ref=sr_1_1?s=books&ie=UTF8&qid=1535265641&sr=1-1&keywords=well-being%3A+the+foundations+of+hedonic+psychology