@PreAuthorize(SecurityRules.IS_OFFICE)
  @RequestMapping(value = "/sicknote", method = RequestMethod.GET)
  public String periodsSickNotes(
      @RequestParam(value = "from", required = false) String from,
      @RequestParam(value = "to", required = false) String to,
      Model model) {

    FilterPeriod period = new FilterPeriod(Optional.ofNullable(from), Optional.ofNullable(to));

    List<SickNote> sickNoteList =
        sickNoteService.getByPeriod(period.getStartDate(), period.getEndDate());

    fillModel(model, sickNoteList, period);

    return "sicknote/sick_notes";
  }