David O. Johnson Raymond H. Cuijpers Investigating the Effect of a Humanoid Robot's Head Position on Imitating Human Emotions. 65-74 2019 11 Int. J. Soc. Robotics 1 https://doi.org/10.1007/s12369-018-0477-4 https://www.wikidata.org/entity/Q129960088 db/journals/ijsr/ijsr11.html#JohnsonC19