Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '72.18.91.0'
+192
ERRNo PTR record availible DNS server 'betty.ns.cloudflare.com' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.91.18.72.in-addr.arpa'.