Dear Ryoji,
You can see how to deduce the Newton law of gravitation in the concept of gravitons in the paper: Fedosin S.G. Model of Gravitational Interaction in the Concept of Gravitons. // Journal of Vectorial Relativity, March 2009, Vol. 4, No. 1, P.1-24. The concept of gravitons in the framework of Le Sage approach leads then to Covariant theory of gravitation and determination of energy and mass. By the way you can evaluate my essay.