Install postgreSQL 9.0 in Linux Ubuntu 9.10

Dear all,
i tried to install postgresql 9.0 in my Linux Ubuntu 9.10. I follow these
steps that i found in:

http://www.russbrooks.com/2010/12/4/install-postgresql-9-on-ubuntu-linux

I know that : Tested on: Ubuntu 10.04

I received this error:

$ sudo apt-get install postgresql-9.0
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
postgresql-9.0: Depends: libc6 (>= 2.11) but 2.10.1-0ubuntu19 is to be
installed
Depends: libgssapi-krb5-2 (>= 1.8+dfsg) but 1.7dfsg~beta3-
1ubuntu0.13 is to be installed
Depends: libssl0.9.8 (>= 0.9.8k-1) but 0.9.8g-16ubuntu3.5 is
to be installed
Depends: postgresql-client-9.0 but it is not going to be
installed
E: Broken packages

Where i can found a documentation about how can i install postgresq 9.0 in
Ubuntu 9.10?

Thanks

Francesco Boccacci