APA (7th ed.) Citation

Summers, H. (2007). The Book Of Happiness: 21 hari yang mengubah hidup. PT. Gramedia Pustaka Utama.

Chicago Style (17th ed.) Citation

Summers, Heather. The Book Of Happiness: 21 Hari Yang Mengubah Hidup. PT. Gramedia Pustaka Utama, 2007.

MLA (8th ed.) Citation

Summers, Heather. The Book Of Happiness: 21 Hari Yang Mengubah Hidup. PT. Gramedia Pustaka Utama, 2007.

Warning: These citations may not always be 100% accurate.