@inproceedings{Väisänen:2021Ki, author = "Väisänen, Pauli and Usoskin, Ilya and Mursula, Kalevi", title = "{Quality survey of Neutron Monitor data sources for 1951-2019}", doi = "10.22323/1.395.1244", booktitle = "Proceedings of 37th International Cosmic Ray Conference {\textemdash} PoS(ICRC2021)", year = 2021, volume = "395", pages = "1244" }