On the Riesz means of the solutions of the Schrödinger equation
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 3, Volume 24 (1970) no. 2, p. 331-348 
@article{ASNSP_1970_3_24_2_331_0,
     author = {Sj\"ostrand, Sigrid},
     title = {On the Riesz means of the solutions of the Schr\"odinger equation},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     publisher = {Scuola normale superiore},
     volume = {Ser. 3, 24},
     number = {2},
     year = {1970},
     pages = {331-348},
     zbl = {0201.14901},
     mrnumber = {270219},
     language = {en},
     url = {http://www.numdam.org/item/ASNSP_1970_3_24_2_331_0}
}

Sjöstrand, Sigrid. On the Riesz means of the solutions of the Schrödinger equation. Annali della Scuola Normale Superiore di Pisa - Classe di Scienze, Série 3, Volume 24 (1970) no. 2, pp. 331-348. http://www.numdam.org/item/ASNSP_1970_3_24_2_331_0/

[1] I.M. Gelfand and G.E. Schilow, Verallgemeinerte Funktionen (Distributionen) I, VEB Deutscher Verlag der Wissenschaften, Berlin 1960. | MR 115086 | Zbl 0122.11401

[2] L. Hörmander, Estimates for translation invariant operators in Lp- spaces, Acta Math. 104 (1960), 93-140. | MR 121655 | Zbl 0093.11402

[3] E. Lanconelli, Valutazioni in Lp (Rn) della soluzione del problema di Cauchy per l'equazione di Sohrödinger, Boll. Un. Mat. Ital (1968), 591-607, | MR 234133 | Zbl 0167.10401

[4] W. Littman, C. M and N. Riviere, The non-existence of Lp-estimates for certain translation-invariant operators, Studie Math. 30. (1968), 219-229. | MR 231127 | Zbl 0162.18401

[5] J. Löfström, Besov spaces in the theory of approximation, Ann. Mat. Pura Appl.. 85 (1970), 93-184. | MR 267332 | Zbl 0193.41401

[6] J. Peetre, Applications de la théorie des espaces d'interpolation dans l'Analyse Harmonique, Ricerche Mat. 15 (1966), 3-36. | MR 221214 | Zbl 0154.15302

[7] J. Peetre, Sur la théorie des semi-groupes distributions, Collège de France, séminaires sur les equations aux dérivées partielles II, nov. 1963-mai 1964, 76-99. | Numdam | MR 512913

[8] S. Wainger, Special trigonometric series in k-dimensions, Mem. Amer. Math. Soc 59 (1965). | MR 182838 | Zbl 0136.36601