These entries are queried from radb.net using whois, you can try my project getting these.
:AS15373 route: 212.87.224.0/21 descr: The network of Technical University of Czestochowa descr: Czestochowa,POLAND origin: AS15373 remarks: operational mnt-by: PL-CZESTMAN-MNT created: 1970-01-01T00:00:00Z last-modified: 2001-09-22T09:33:21Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid route: 212.87.232.0/23 descr: Networks of universities in Czestochowa descr: Czestochowa,POLAND origin: AS15373 remarks: operationa mnt-by: PL-CZESTMAN-MNT created: 2012-12-17T15:15:16Z last-modified: 2015-07-02T14:22:10Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid route: 212.87.234.0/23 descr: Networks of Akademia im. Jana Dlugosza, Czestochowa, Poland origin: AS15373 remarks: operational mnt-by: PL-CZESTMAN-MNT created: 1970-01-01T00:00:00Z last-modified: 2015-07-02T15:17:12Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid route: 212.87.236.0/23 descr: The network of Polonia University in Czestochowa descr: Czestochowa,POLAND origin: AS15373 remarks: operationa mnt-by: PL-CZESTMAN-MNT created: 2012-12-17T15:21:04Z last-modified: 2012-12-17T15:21:04Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid route: 212.87.238.0/23 descr: The networks of educational, scientific, governmental descr: health, cultural, religious, research subjects descr: Metropolitan Area Network CzestMAN, Czestochowa,POLAND origin: AS15373 remarks: educational mnt-routes: PL-CZESTMAN-MNT mnt-by: PL-CZESTMAN-MNT created: 2006-03-02T15:56:54Z last-modified: 2006-03-02T15:56:54Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid route: 212.87.253.0/24 origin: AS15373 mnt-by: PL-CZESTMAN-MNT created: 2023-10-27T11:38:41Z last-modified: 2023-10-27T11:40:37Z source: RIPE remarks: Educational descr: The networks of educational, scientific, governmental, health, cultural, religious, research subjects Metropolitan Area Network CzestMAN, Czestochowa, POLAND remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid route6: 2a01:698::/32 descr: The network of Technical University of Czestochowa descr: Czestochowa,POLAND origin: AS15373 remarks: operational mnt-by: PL-CZESTMAN-MNT created: 2010-04-20T09:31:23Z last-modified: 2010-04-20T09:31:23Z source: RIPE remarks: **************************** remarks: * THIS OBJECT IS MODIFIED remarks: * Please note that all data that is generally regarded as personal remarks: * data has been removed from this object. remarks: * To view the original object, please query the RIPE Database at: remarks: * http://www.ripe.net/whois remarks: **************************** rpki-ov-state: valid