These entries are queried from radb.net using whois, you can try my project getting these.
:AS-DROPBOX as-set: AS-DROPBOX descr: 333 Brannan St, San francisco, CA- 94107 members: AS19679 tech-c: radb-contact mnt-by: MAINT-AS19679 changed: raghav [at] dropbox.com 20161215 #22:28:58Z source: RADB