1. J.J. Duistermaat, Fourier Integral Operators. Progress in Mathematics, vol. 130 (Birkhäuser, Basel, 1994)
2. Yu.V. Egorov, Canonical transformations and pseudodifferential operators. Trans. Moscow Math. Soc. 24, 3–28 (1971)
3. A. Grigis, J. Sjöstrand, Microlocal Analysis for Differential Operators. London Mathematical Society Lecture Note Series, vol. 196 (Cambridge University Press, Cambridge, 1994)
4. L. Hörmander, The Analysis of Linear Partial Differential Operators. I. Grundlehren Math. Wiss., vol. 274 (Springer, Berlin, 1983)
5. L. Hörmander, The Analysis of Linear Partial Differential Operators. III. Grundlehren Math. Wiss., vol. 274 (Springer, Berlin, 1985)