I had several because I had the chance to meet famous whisperers but also very good whisperers who are not mediatized.
If I limit myself to a few I will say:
Pat Parelli with whom I spent more than 5 years, who taught me all the technique but also the pedagogical aspect of what I teach.
Ray Hunt that I had the chance to rub shoulders regularly.
Andrew Mclean that I've known quite recently, which helps me put scientific words on technique and understand why the work of American whisperers works so well.
Without forgetting one of my main equine mentors: Stormy, thanks to whom I understood that one should educate a horse as one should educate a zebra.
I also created a DVD to explain what is called "stormy, my mentor": http://www.andybooth.fr/dvd.html