A Relativistic $O(a^2)$ Improved Action for Heavy Quarks
  We extend the Fermilab formalism for heavy quarks to develop an $O(a^2)$ improved relativistic action. We discuss our construction of the action, including the identification of redundant operators and the calculation of the improvement coefficients. 
M.B. Oktay, A.X. El-Khadra, A.S. Kronfeld, P.B. Mackenzie, J.N. Simone