Visual determination of sleep states is published in the journal Sleep. Congratulations to Brian and Mandy for leading this effort.
The article can be found here.
Standard link (you may share this link anywhere):
https://academic.oup.com/sleep/advance-article-abstract/doi/10.1093/sleep/zsab260/6414386
Free-access link (see below for how you may use this link):
https://academic.oup.com/sleep/advance-article/doi/10.1093/sleep/zsab260/6414386?guestAccessKey=69d52bfe-bbe4-4aef-b1de-77f1b380bc86