Kok, Bethany E. Department Social Neuroscience, MPI for Human Cognitive and Brain Sciences, Max Planck Society;
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5854504/ (Publisher version)
Fredrickson, B. L., & Kok, B. E. (2018). Evidence for the upward spiral stands steady: A response to Nickerson. Psychological Science, 29(3), 467-470. doi:10.1177/0956797617707319.