MLA 8th edition
Last Name, First Name of video creator or Username of Creator. "Title of Video." Title of the Hosting Website, Day Month Year of Publication, URL of video. Accessed Day Month Year video was viewed.
APA 6th edition
Lastname, Firstname [or single username]. (Year, month day posted). Title of YouTube Video. [Video file]. Retrieved from URL
Chicago 17th edition
Lastname, Firstname [or single username]. "Title of YouTube Video." YouTube, Month day, year posted. Video, length of video. URL.