These entries are queried from radb.net using whois, you can try my project getting these.
:AS23907 route: 192.18.16.0/20 descr: Sun Singapore origin: AS23907 notify: tony.tan [at] sun.com mnt-by: MAINT-AP-SUN changed: tony.tan [at] sun.com 20031002 source: NTTCOM rpki-ov-state: not_found # No ROAs found, or RPKI validation not enabled for source