Bill Olson states:
  I consider Ted Sannella to be one of my primary mentors and back in  
 the early days I did sound and often played in the band for his 4th  
 Friday dance in North Whitefield, ME, so I got to see him close up..  
 Ted ALWAYS used cards but I KNEW he new the dances he called from  
 memory. I asked him about it once and he said it just made him feel  
 safer up there.. 
Another motivation for Ted may have been the fact that he kept  
meticulous notes ----the date, place, and the dances that he called.  
His extensive collection of personal notes, as well as books, and many  
other items were donated to the Special Collections archives at the  
University of New Hampshire. Here is the link to the information about  
Ted:
http://www.library.unh.edu/special/index.php/ted-sannella
Linda