Retni, Ani, and Fatmah M Abdullah. “Effectiveness of the Stimulation of Endorphin, Oxytocin, and Serotonin (SPEOS) Method in Improving Sleep Quality Among Postpartum Women: A Quasi-Experimental Study in Primary Maternal Healthcare in Gorontalo, Indonesia”. Journal of Health and Nutrition Research 5, no. 2 (August 1, 2026): 1048–1057. Accessed August 6, 2026. https://journalmpci.com/index.php/jhnr/article/view/1469.