Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/wrinkles/symptoms-causes/syc-20354927
https://www.mayoclinic.org/healthy-lifestyle/quit-smoking/expert-answers/smoking/faq-20058153
Diakses 10 Mei 2019Live Strong. https://www.livestrong.com/article/202253-how-to-get-rid-of-wrinkles-from-my-hands/
Diakses 10 Mei 2019Huffington Post. https://www.huffpost.com/entry/body-parts-that-age-you_n_5106216?guccounter=1&guce_referrer=aHR0cHM6Ly93d3cuZ29vZ2xlLmNvbS8&guce_referrer_sig=AQAAANQhj07fYso8hDq0gafm9XeckdySjIodUKF2lYF1RT6eeq7o9tQiCUi7oT52UyzktDHdDwdTAtOY1qxdFk3wsPALVuKLMts8DSUfVqTDsr4KKFklfwRiBZH8GHvYbPOK_XEpHSykW1bJYq1Bepv0mxmcyiZqqnRNZq3zFjDDCV8z
Diakses 10 Mei 2019