static <A extends Concept> L<A> findBackRefsWithField(Concept c, Class<A> type, S field) {
  ret filter(findBackRefs(c, type), o -> cget(o, field) == c);
}
  
static <A extends Concept> L<A> nuLike findBackRefsWithField(Class<A> type, Concept c, S field) {
  ret findBackRefsWithField(c, type, field);
}

static <A extends Concept> L<A> nuLike findBackRefsWithField(Class<A> type, S field, Concept c) {
  ret findBackRefsWithField(c, type, field);
}