As a result of these factors, the exact death toll of the entire system of Mauthausen and its subcamps varies considerably from source to source. Various scholars place it at between 122,766 and 320,000, with other numbers also frequently quoted being 200,000 and "over 150,000". Various historians place the total death toll in the four main camps of Mauthausen, Gusen I, Gusen II and Gusen III at between 55,000 and 60,000. In addition, during the first month after the liberation additional 1,042 prisoners died in American field hospitals.