Frailey L.E & Mamchak Susan. (1993). Hanbook of Business Letters (3rd Edition.). Super Book House.
Citazione stile Chigago Style (17a edizione)Frailey L.E e Mamchak Susan. Hanbook of Business Letters. 3rd Edition. Bombay: Super Book House, 1993.
Citatione MLA (9a ed.)Frailey L.E e Mamchak Susan. Hanbook of Business Letters. 3rd Edition. Super Book House, 1993.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.