* {{cita libro|autore=Di W. P. Edwards|titolo=The Science of Sugar Confectionery|editore=Royal Society of Chemistry|ISBN=0-85404-593-7|anno=2000|pagine=101-109|url=http://books.google.it/books?id=JTdUXI9fz2kC&pg=PA102&dq=Toffee+sugar&hl=it&sa=X&ei=ab1gU-O0JeeS0QWOwIG4BQ&ved=0CDIQ6AEwAA#v=onepage|lingua=en|capitolo=Toffees and caramel}}
*{{cita libro|autore=Di NPCS Board|titolo=Confectionery Products Handbook|editore=ASIA PACIFIC BUSINESS PRESS Inc.|ISBN=81-7833-153-5|anno=2013|pagine=435-449|url=http://books.google.it/books?id=a989AQAAQBAJ&pg=PA455&dq=Toffee+sugar&hl=it&sa=X&ei=ab1gU-O0JeeS0QWOwIG4BQ&ved=0CDoQ6AEwAQ#v=onepage&q=Toffee%20sugar&f=false|lingua=en}}
