Ichihara, E., N. Takigawa, K. Kato, Y. Tanimoto, I. Yamadori, K. Kiura, and M. Tanimoto. “Migrating Ground Glass Opacities on Computed Tomography Due to Gravitation in a Patient With Pulmonary Alveolar Proteinosis”. Chest Disease Reports, Vol. 1, no. 1, Apr. 2011, p. e2, doi:10.4081/cdr.2011.e2.