jquery validate Uncaught TypeError: $ (...) .validate is not a function

$( document ).ready(function() {
  var validator = $( "#form-crear" ).validate();
  validator.form();
  console.log(validator);
});

<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.0/jquery.validate.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.0/additional-methods.min.js"></script>

<form class="form-horizontal" role="form" id="form-crear">
  <div class="modal-body">
    <div class="form-group">
      <label for="crear_nombre" class="control-label col-sm-2">Nombre: </label>
      <div class="col-sm-10">
        <input type="text" class="form-control" id="crear_nombre" name="crear_nombre">
      </div>
    </div>
  </div> 
  <div class="modal-footer">
  </div>
</form>