Clue! - as you know doubt are now aware, VERIO and Jippi are -two-
of the tens of thousands of ISPs that make up the catanet that is the
Internet. The published filtering policies of these two providers is
a useful tool for others to determine why VERIO and Jippi are contributing
to "odd" routing.
WRT learning more, you may wish to review the IETF's CIDRd WG archives
from 1993-1997. You may also wish to review RFC 2050 and the various
RIR policies on the evolution of that work.