Edwin Sachs published "Changing Die" in his book Sleight of Hand in 1877. (The idea of using a paddle move to show the same side of a die twice was an old idea even back then.)
Decades later, Bruce Elliott published an improved version called Sack's Spotted Sorcery - Phoenix #152, p. 615. That's the one you want to start with. Other people (Bob Sheets, Daryl, James Lewis, Reed McClintock etc) are all building on the Sack's routine.
The Sach/Sack's thing is just a coincidence. Edwin Sachs died in 1919. Dr. Theodore Sack didn't release his version of the effect until the late 1940s.