@article{701436,
     title = {Conformal transformation, conformal change, and conformal covariants},
     booktitle = {Proceedings of the Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {1989},
     pages = {[115]-134},
     mrnumber = {MR1009568},
     zbl = {0678.53025},
     url = {http://dml.mathdoc.fr/item/701436}
}

Branson, Thomas P. Conformal transformation, conformal change, and conformal covariants, dans Proceedings of the Winter School "Geometry and Physics", GDML_Books,  (1989), pp. [115]-134. http://gdmltest.u-ga.fr/item/701436/