The Conquest of happiness / Bertrand Russell

Stability of happiness : theories and evidence on whether happiness can change / edited by Kennon M. Sheldon, Richard E. Lucas

Pengaruh kedekatan hubungan antara pemberi dan penerima tindakan baik terhadap kebahagiaan = The effect of closeness between giver and receiver act of kindness on happiness

Lebih baik sekarang daripada nanti: pengaruh waktu pemberian umpan balik dari penerima surat terima kasih terhadap kebahagiaan pengirim = Better now than later: the effect of delayed feedback from receiver of gratitude letter towards sender's happiness

The art of happiness: mencipta kebahagiaan dalam setiap keadaan/Khalil A. Khavari