anchor.diff:                      <p>
                           <fmt:message key="view.reference.detail"/> :
                           <c:forEach var="publication" items="${publications}">
  -                            <%-- pubmed url--%>
  -                            <spring:url var="pubmedIdUrl" value="http://europepmc.org/abstract/MED/{pubmedId}">
  -                                <spring:param name="pubmedId" value="${publication.pubmedId}"/>
  -                            </spring:url>
  -
  -                            <a href="${pubmedIdUrl}" target="_blank">${publication.pubmedId}</a>
  +                            <c:if test="${publication.pubmedId gt 0}">
  +                                <%-- pubmed url--%>
  +                                <spring:url var="pubmedIdUrl" value="http://europepmc.org/abstract/MED/{pubmedId}">
  +                                    <spring:param name="pubmedId" value="${publication.pubmedId}"/>
  +                                </spring:url>
  +
  +                                <a href="${pubmedIdUrl}" target="_blank">${publication.pubmedId}</a>
  +                            </c:if>
  +                            <c:if test="${publication.pubmedId eq 0}">
  +                                <%-- doi url--%>
  +                                <spring:url var="doiUrl" value="http://dx.doi.org/{doi}">
  +                                    <spring:param name="doi" value="${publication.doi}"/>
  +                                </spring:url>
  +                                <a href="${doiUrl}" target="_blank">${publication.doi}</a>
  +                            </c:if>
                           </c:forEach>
                       </p>
                   </c:when>
  
positive.code:         <c:when test="${not empty publications}">
              <ul>
                  <c:forEach var="publication" items="${publications}">
                      <%-- pubmed url--%>
                      <spring:url var="pubmedIdUrl" value="http://europepmc.org/abstract/MED/{pubmedId}">
                          <spring:param name="pubmedId" value="${publication.pubmedId}"/>
                      </spring:url>
  
                      <p>
                              ${publication.referenceLine}
                          <fmt:message key="pubmed"/> : <a href="${pubmedIdUrl}"
                                                           target="_blank">${publication.pubmedId}</a>
                      </p>
                  </c:forEach>
              </ul>
          </c:when>
  
negative.code:                     <p>
                          <fmt:message key="view.reference.detail"/> :
                          <c:forEach var="publication" items="${publications}">
                              <c:if test="${publication.pubmedId gt 0}">
                                  <%-- pubmed url--%>
                              <spring:url var="pubmedIdUrl" value="http://europepmc.org/abstract/MED/{pubmedId}">
                                  <spring:param name="pubmedId" value="${publication.pubmedId}"/>
                              </spring:url>
  
                              <a href="${pubmedIdUrl}" target="_blank">${publication.pubmedId}</a>
                              </c:if>
                              <c:if test="${publication.pubmedId eq 0}">
                                  <%-- doi url--%>
                                  <spring:url var="doiUrl" value="http://dx.doi.org/{doi}">
                                      <spring:param name="doi" value="${publication.doi}"/>
                                  </spring:url>
                              <a href="${doiUrl}" target="_blank">${publication.doi}</a>
                              </c:if>
                          </c:forEach>
                      </p>
                  </c:when>
  