https://en.wikipedia.org/wiki/Jaak_Panksepp
https://www.nature.com/articles/npp2017168
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344464/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181986/
https://royalsocietypublishing.org/doi/full/10.1098/rspb.2010.1017
https://www.amazon.com/Archaeology-Mind-Neuroevolutionary-Interpersonal-Neurobiology/dp/0393705315/ref=sr_1_1?qid=1579832656&refinements=p_27%3AJaak+Panksepp+PhD&s=books&sr=1-1&text=Jaak+Panksepp+PhD
https://www.amazon.com/Emotional-Foundations-Personality-Neurobiological-Evolutionary/dp/0393710572/ref=sr_1_3?keywords=Jaak+Panksepp&qid=1579832402&s=books&sr=1-3
https://www.amazon.com/Affective-Neuroscience-Foundations-Emotions-Science/dp/019517805X/ref=sr_1_1?keywords=Jaak+Panksepp&qid=1579833214&s=books&sr=1-1