Add link to WLCG repo

README-el7.md

@@ -107,9 +107,8 @@ the HEP_OSlibs meta-rpm's in this repository are signed with this key,
 as described [here](http://linuxsoft.cern.ch/wlcg/__README__).
 
 The easiest way to install HEP_OSlibs from the WLCG repository consists
-in first installing the wlcg-repo rpm describing the wlcg repository
-and then installing HEP_OSlibs, as follows:
-
+in first installing the [wlcg-repo rpm](https://linuxsoft.cern.ch/wlcg/centos7/x86_64/wlcg-repo-1.0.0-1.el7.noarch.rpm)
+describing the wlcg repository and then installing HEP_OSlibs, as follows:
 ```bash
   yum install https://linuxsoft.cern.ch/wlcg/centos7/x86_64/wlcg-repo-1.0.0-1.el7.noarch.rpm
   yum install HEP_OSlibs