code: public List<I_CmsHistoryResource> readAllAvailableVersions(String resourceName) throws CmsException {
  
          CmsResource resource = readResource(resourceName, CmsResourceFilter.ALL);
          return m_securityManager.readAllAvailableVersions(m_context, resource);
      }
docs: Reads all historical versions of a resource.<br>
  
  The reading excludes the file content, if the resource is a file.<p>
  
  @param resourceName the name of the resource to be read
  
  @return a list of historical resources, as <code>{@link I_CmsHistoryResource}</code> objects
  
  @throws CmsException if operation was not successful