Option Pricing from Path Integral for Non-Gaussian Fluctuations. Natural   Martingale and Application to Truncated L\'evy Distributions
  Within a path integral formalism for non-Gaussian price fluctuations we set up a simple stochastic calculus and derive a natural martingale for option pricing from the wealth balance of options, stocks, and bonds. The resulting formula is evaluated for truncated L\'evy distributions. 
Hagen Kleinert