Boyer, Paul S. Purity in Print: Censorship from the Gilded Age to the Computer Age. Also all-around this time, in June 1970, the 55th Street Playhouse started showing Censorship in Denmark: A New Approach, a movie documentary research of pornography, directed by Alex de Renzy. Feng, Yunhe Cao, Qing Qi, Hairong Ruoti, Scott (June 2020). "SenCAPTCHA: A Mobile-First CAPTCHA Using Orientation Sensors". Johnson, Bobbie (6 June 2008).