Thank you Wierd Folkersma!
At Duane Michals´ exhibition at the Museum of Moder Art (MOMA) in New York in 1970, If you want to see what some of them are looking at (instead of the photos of D. Michals) look at PIP 3.
What I was fascinated with, (apart of his visitors) were his photos called Sequences. That was a time Photoshop didn´t even exist.