@article{701737,
     title = {Conservation of pseudo-norm in $\mathcal {P}\mathcal {T}$ symmetric quantum mechanics},
     booktitle = {Proceedings of the 23rd Winter School "Geometry and Physics"},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {2004},
     pages = {[211]-218},
     mrnumber = {MR2069409},
     zbl = {1052.46010},
     url = {http://dml.mathdoc.fr/item/701737}
}

Znojil, Miloslav. Conservation of pseudo-norm in $\mathcal {P}\mathcal {T}$ symmetric quantum mechanics, dans Proceedings of the 23rd Winter School "Geometry and Physics", GDML_Books,  (2004), pp. [211]-218. http://gdmltest.u-ga.fr/item/701737/