Route Views

Hello,
  Some prefixes in the Route Views routing table do not have a prefix
length specified. For example,
  4.0.0.0 and 61.0.0.0 do not have a prefix length specified in the Route
Views routing table. 61/8 belongs to APNIC. 4/8 belongs to Genuity.

  Why is this? How does one find out the prefix length in such cases?

Harsha.

  Some prefixes in the Route Views routing table do not have a prefix
length specified. For example,

because they are their 'natural' length, i.e. old style A/B/C