(BSM - two seminal 1973 papers [20] [21] - is consistent with "previous versions of the formula" of Louis Bachelier (1900) and Edward O. Thorp (1967);[22] although these were more "actuarial" in flavor, and had not established risk-neutral discounting.[6] See also Paul Samuelson (1965).[23] Vinzenz Bronzin (1908) produced very early results, also.)