Rudolf, M., 		Koren, T., & 		Žiljak Vujić, J.
(2017).
 New Postage Stamp Design With Tone Gradation in Infrared Design Technology.
<em>Acta Graphica, 23</em>(3-4), 57-64.
Retrieved from <a href="https://actagraphica.hr/index.php/actagraphica/article/view/83" target="_new">https://actagraphica.hr/index.php/actagraphica/article/view/83</a>