deb http://security.debian.org/ wheezy/updates main contrib
deb-src http://security.debian.org/ wheezy/updates main contrib
+# backports:
+ deb http://http.debian.net/debian wheezy-backports main
+ deb-src http://http.debian.net/debian wheezy-backports main
+
# official debian repository:
# deb http://ftp.debian.org/debian/ wheezy main contrib non-free
# deb-src http://ftp.debian.org/debian/ wheezy main contrib non-free