<ul class=“icons”>

{% if site.twitter_username %}
    <li class="icon">
        <a href="https://twitter.com/{{ site.twitter_username }}" class="fa fa-twitter" title="Twitter"></a>
    </li>
{% endif %}
{% if site.github_username %}
    <li class="icon">
        <a href="https://github.com/{{ site.github_username }}" class="fa fa-github" title="GitHub"></a>
    </li>
{% endif %}
{% if site.gitlab_username %}
    <li class="icon">
        <a href="https://gitlab.com/{{ site.gitlab_username }}" class="fa fa-gitlab" title="GitLab"></a>
    </li>
{% endif %}
{% if site.scholar_username %}
    <li class="icon">
        <a href="https://scholar.google.pt/citations?user={{ site.scholar_username }}" class="fa fa-graduation-cap" title="Google Scholar"></a>
    </li>
{% endif %}

</ul>