no. 1
On some Schrödinger operators with a singular complex potential
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 4, Tome 5 (1978) no. 1, pp. 105-114. 
@article{ASNSP_1978_4_5_1_105_0,
     author = {Kato, Tosio},
     title = {On some Schr\"odinger operators with a singular complex potential},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {105--114},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 5},
     number = {1},
     year = {1978},
     zbl = {0376.47021},
     mrnumber = {492961},
     language = {en},
     url = {archive.numdam.org/item/ASNSP_1978_4_5_1_105_0/}
}
Kato, Tosio. On some Schrödinger operators with a singular complex potential. Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 4, Tome 5 (1978) no. 1, pp. 105-114. http://archive.numdam.org/item/ASNSP_1978_4_5_1_105_0/

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