Hofland, Regina W, Steven FT Thijsen, John Bouwman, Myrtle van der Wel, and Ailko WJ Bossink. 2014. “Sarcoidosis and Purified Protein Derivative Reactivity”. Sarcoidosis, Vasculitis and Diffuse Lung Diseases 31 (2): 142-48. https://mattioli1885journals.com/index.php/sarcoidosis/article/view/2894.