private List<Family> getFamilies(Gedcom gedcom, List<? extends SpouseFamilyRef> familyRefs) {
      List<Family> families = new ArrayList<Family>();
      for (SpouseFamilyRef familyRef : familyRefs) {
         Family family = familyRef.getFamily(gedcom);
         if (family != null) {
            families.add(family);
         }
      }
      return families;
   }