DNS requests for 1918 space

["Geo." <georger () getinfo net>]

Can anyone point me at any papers that talk about security issues raised by
private networks passing dns requests for RFC 1918 private address space out
to their ISP's dns servers?

I'm aware of the issues involved with an ISP passing the requests on to the
root servers but was looking specifically for security type issues relating
to a private network passing the requests out to their ISP's dns servers.

Geo.