Paolo Piccione, Daniel V. Tausk: A student’s guide to symplectic spaces, Grassmannians and Maslov index, Instituto de Matemática Pura e Aplicada (2011) [pdf, pdf]
Leandro A. Lichtenfelz, Paolo Piccione, Abdelghani Zeghib, On the Isometry Group of Lorentz Manifolds, in: Miguel Sanchez, Miguel Ortega, Alfonso Romero (eds.) Recent Trends in Lorentzian Geometry, Springer 2013 (doi:10.1007/978-1-4614-4897-6_12)