Other well known vocalists who endorsed the initiative include Shirley Verrett (soprano), Joan Sutherland (soprano), George Shirley (tenor), Luciano Pavarotti (tenor), Sherrill Milne (baritone), Fedora Barbier (mezzosoprano), Grace Bumbry (soprano), Elly Ameling (soprano), Peter Schreier (tenor), Birgit Nilsson (soprano), Dietrich Fischer-Dieskau (baritone), Kurt Moll (basso), Marilyn Horne (mezzosoprano), and Ruggero Raimondi (basso).
Mitchell also serves on the Board of Directors of the LaRouche Movement's Schiller Institute.
Massachusetts Institute of Technology | California Institute of Technology | Art Institute of Chicago | Institute for Advanced Study | American Institute of Architects | Georgia Institute of Technology | Friedrich Schiller | Rensselaer Polytechnic Institute | Rochester Institute of Technology | Franklin Institute | Royal Institute of Technology | Pasteur Institute | Institute of Contemporary Arts | California Institute of the Arts | Institute of Electrical and Electronics Engineers | British Film Institute | Pratt Institute | National Cancer Institute | Virginia Military Institute | Cato Institute | Australian Institute of Sport | Illinois Institute of Technology | Curtis Institute of Music | American Institute of Aeronautics and Astronautics | Royal Institute of British Architects | National Institute of Standards and Technology | Monterrey Institute of Technology and Higher Education | Institute of Physics | List of Monterrey Institute of Technology and Higher Education faculty | Weizmann Institute of Science |