Unable to find any PTR-records for the specified domain/ip :(
Log
+000
Resolving PTR record of '91.193.42.0'
+175
ERRNo PTR record availible DNS server 'ns-1684.awsdns-18.co.uk' raised an NotExistentDomain error, while beeing queried for PTR-records on domain '0.42.193.91.in-addr.arpa'.