Access Jquery UI using primefaces

Access Jquery UI using primefaces

I am building a JSF application and want to convert a simple h:link to
look like a button using jquery ui button widget. I am using JSF2 and
primefaces 3.5.
I manually added the jquery-ui.js and have the following xhtml:
<h:link styleClass="linkGr"
outcome="#{listadoUsuario.verUser(user.username)}">ver</h:link>
<script>$(".linkGr").button({icons: {primary: "ui-icon-pencil"},text:
false});</script>
Having this in a page works fine, but in other pages, I see the following
error:
TypeError: Object function (f,h,e){var
g=f.split(".")[0],j;f=f.split(".")[1];j=g+"-"+f;if(!e){e=h;h=b.Widget}b.expr[":"][j]=function(k){return
!!b.data(k,f)};b[g]=b[g]||{};b[g][f]=function(k,l){if(arguments.length){this._createWidget(k,l)}};var
i=new
h();i.options=b.extend(true,{},i.options);b[g][f].prototype=b.extend(true,i,{namespace:g,widgetName:f,widgetEventPrefix:b[g][f].prototype.widgetEventPrefix||f,widgetBaseClass:j},e);b.widget.bridge(f,b[g][f])}
has no method 'extend'
I noted that this happens in pages where primefaces adds the
jquery-plugins.js.
I tried not including the jquery-ui javascript manually since I see the
jquery-plugins adds the button widget, but the problem is when adding
jquery-plugins (not including jquery-ui.js) I cannot see how to convert
the link to a button. The function button is not available in $. Can
somebody guide me on how to use primefaces included button method?
Thanks in advance!