The thickness of avian blood-gas barrier: qualitative and quantitative observations.
D000818:Animals; D001699:Biometry; D001717:Birds / Q000033:anatomy & histology*; D002196:Capillaries / Q000648:ultrastructure; D004848:Epithelium / Q000648:ultrastructure; D008168:Lung / Q000098:blood supply / Q000648:ultrastructure*; D008854:Microscopy, Electron