<input name="author.name" ng:required>
<input name="author.surname" ng:required>
<input name="author.inst" >
<input name="author.email" ng:required>
</div>
<input name="author.name" ng:required>
<input name="author.surname" ng:required>
<input name="author.inst" >
<input name="author.email" ng:required>
</div>