@article{article324982d9,
title   = {Characteristics-based boundary conditions for the Euler adjoint problem},
author = {Hayashi, Marcelo Tanaka and Ceze, Marco Antonio de Barros and Volpe, Ernani Vitillo},
year = {2013},
doi = {10.1002/fld.3641},
journal   = {International Journal for Numerical Methods in Fluids}
}