Matteo Corti <matteo@corti.li>
Elan Ruusamäe <glen@delfi.ee> (improved parallel support and several fixes)
Victor V Kudlak <info@kentos.ru> (parallel support)
Jan Kantert <jan.kantert@researchgate.net> for the whitelisting support
Nick Nicholas <opoudjis@gmail.com> for IPv6 support
Michael Orlitzky <michael@orlitzky.com> for the test.sh usage patch 
Celevra https://github.com/celevra for the Debian/Ubuntu documentation update
Claudio Kuenzler https://github.com/Napsty for the append patch

Please report any bugs or feature requests through the
web interface at https://github.com/matteocorti/check_rbl/issues