% APNIC found the following authoritative answer from: whois.ripe.net

% This is the RIPE Database query service.
% The objects are in RPSL format.
%
% The RIPE Database is subject to Terms and Conditions.
% See https://docs.db.ripe.net/terms-conditions.html

% Note: this output has been filtered.
%       To receive output for a database update, use the "-B" flag.

% Information related to '83.208.55.0 - 83.208.55.255'

% Abuse contact for '83.208.55.0 - 83.208.55.255' is 'abuse@o2.cz'

inetnum:        83.208.55.0 - 83.208.55.255
netname:        NEXTEL-XDSL
descr:          XDSL NETWORK-ADSL
country:        CZ
admin-c:        HVJI1-RIPE
tech-c:         HVJI1-RIPE
status:         ASSIGNED PA
mnt-by:         AS5610-MTN
created:        2004-08-10T07:48:07Z
last-modified:  2004-08-10T07:48:07Z
source:         RIPE # Filtered

person:         Jiri Hvezda
address:        O2 Czech Republic, a.s.
address:        Za Brumlovkou 2
address:        Prague 4 - 140 22
address:        The Czech Republic
phone:          +420 2 84084222
nic-hdl:        HVJI1-RIPE
created:        2002-07-22T13:31:48Z
last-modified:  2020-06-25T13:10:19Z
source:         RIPE # Filtered
mnt-by:         AS5610-MTN

% Information related to '83.208.0.0/18AS5610'

route:          83.208.0.0/18
descr:          CZ.CZNET
origin:         AS5610
mnt-by:         AS5610-MTN
created:        2010-12-08T13:26:06Z
last-modified:  2010-12-08T13:26:06Z
source:         RIPE

% This query was served by the RIPE Database Query Service version 1.116 (DEXTER)