Ōkawa, R. (2009). The science of happiness: 10 principles for manifesting your divine nature. Destiny Books.
Citazione stile Chigago Style (17a edizione)Ōkawa, Ryūhō. The Science of Happiness: 10 Principles for Manifesting Your Divine Nature. Rochester, Vt: Destiny Books, 2009.
Citatione MLA (9a ed.)Ōkawa, Ryūhō. The Science of Happiness: 10 Principles for Manifesting Your Divine Nature. Destiny Books, 2009.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.