code: public List<CmsResource> readSiblings(String resourcename, CmsResourceFilter filter) throws CmsException {
  
          CmsResource resource = readResource(resourcename, filter);
          return readSiblings(resource, filter);
      }
docs: Returns a list of all siblings of the specified resource,
  the specified resource being always part of the result set.<p>
  
  @param resourcename the name of the specified resource
  @param filter a resource filter
  
  @return a list of <code>{@link CmsResource}</code>s that
  are siblings to the specified resource,
  including the specified resource itself.
  
  @throws CmsException if something goes wrong