R help - Dec 2012 - Installing R-2.15.2 in Debian Wheezy/Testing

The current version of R that is available in Wheezy is 2.15.1. However, 
version 2.15.2 is available at CRAN sites.  The site I use is 
http://cran.case.edu/bin/linux/debian which states:

'If you want to have up to date R on wheezy I propose to directly 
install Dirks packages from unstable (sid) by creating a file 
/etc/apt/preferences containing
    Package: *
    Pin: release a=testing
    Pin-Priority: 650

    Package: *
    Pin: release a=unstable
    Pin-Priority: 600

and adding a line for unstable in /etc/apt/sources.list.'

I assume that the preference file should be in /etc/apt and not in 
/etc/apt/preferences.d

My question is what should be the format of the line in the sources.lists?

Thanks in advance

At Mon, 31 Dec 2012 15:38:10 -0500,
Stephen P. Molnar wrote:
> The current version of R that is available in Wheezy is 2.15.1. However, 
> version 2.15.2 is available at CRAN sites.
> ...
> My question is what should be the format of the line in the sources.lists?
Here's what I have:

  deb http://ftp5.gwdg.de/pub/misc/cran/bin/linux/debian squeeze-cran/

Neal