Williams, G., Rotering, L., Samuel, A., Du, J.P. and Crilly, J., 2019. Zoneff, E.R., Baker, K., Sweeny, A., Keijzers, G., Sanderson, J. and Watkins, S., 2019. The prevalence of lung surface abnormalities in a healthy population as detected by a screening lung ultrasound protocol: Comparison between young and older volunteers. Australasian Journal of Ultrasound in Medicine.