Väyrynen, Seppo, Juha Röning, and Ismo Alakärppä. “User-Centered Development of Video Telephony for Servicing Mainly Older Users: Review and Evaluation of an Approach Applied for 10 Years”. Human Technology 2, no. 1 (April 1, 2006): 8–37. Accessed July 16, 2026. https://ht.csr-pub.eu/index.php/ht/article/view/28.