Positivity : groundbreaking research to release your inner optimist and thrive
  MLA
  Fredrickson, Barbara. Positivity : Groundbreaking Research to Release Your Inner Optimist and Thrive. London: Oneworld, 2019.
  APA
  Fredrickson, B. (2019). Positivity : groundbreaking research to release your inner optimist and thrive. London: Oneworld.
  Chicago
  Fredrickson, Barbara, Positivity: Groundbreaking Research to Release Your Inner Optimist and Thrive. London: Oneworld, 2019.