anchor.diff:                          placeholder="Page number(s) (required)..."
                           ng-model="new_ref_location"
                           ng-pattern="numericRangePattern"
  +                        required
                           autocomplete="off")
                       .col-lg-2
   
  
positive.code:                             placeholder="Year published (required)..."
                              ng-model="new_document.year"
                              ng-pattern="yearPattern"
                              autocomplete="off")
  
                  // EXISTING DOC
  
negative.code:         .col-lg-6
              button.btn.btn-block.btn-success(
              ng-click="documentRefSubmit(new_document)"
              ng-disabled="disable_button || newDocumentForm.$invalid") Create reference
          .col-lg-6
              button.btn.btn-block.btn-danger(ng-click="closeDialog()") Cancel