K Luba I have my trusty Dogs Annuel in front of me.Which you should pick up.It is a great book.They usually have them at the pets stores.Like Petsmart.There is the American Pitbull Terrier.And the American Staffordshire Terrier.And the Staffordshire Bull Terrier.The American Pit originated from the bull and terrier types.The same with the staffordshire terrier.The stafordshire bull terrier is much smaller then the other 2.Ans was mixed with the smaller mastiff breeds And the old english mastiff.Hope that helped you a bit Luba.