@article{SIGMA_2023_19_a56,
     author = {Christopher J. Fewster},
     title = {Modified {Green-Hyperbolic} {Operators}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2023},
     volume = {19},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2023_19_a56/}
}