Groell, Reinhard, Gottfried J. Schaffler, and Stephan Schloffer. “Breath-Hold Times in Patients Undergoing Radiological Examinations: Comparison of Expiration and Inspiration With and Without Hyperventilation”. Radiology and Oncology 35, no. 3 (September 1, 2001). Accessed November 5, 2025. https://www.radioloncol.com/index.php/ro/article/view/1441.