a.url-link {
    background:url('../images/internet.svg');
    background-size: 18px 18px;
    background-repeat: no-repeat;
    padding-left: 2rem;
}

a.pdf-link {
    background: url('../images/Haltools_pdf.png');
    background-repeat: no-repeat;
    padding-left: 2rem;
}


a.bibtex-link {
    background: url('../images/Haltools_bibtex3.png');
    background-repeat: no-repeat;
    padding-left: 2rem;
}