S. Englard, S. Seifter: The biochemical functions of ascorbic acid. In: Annual Review of Nutrition. Band 6, 1986, S. 365–406, doi:10.1146/annurev.nu.06.070186.002053.
P. G. P. Ericson, L. Christidis, A. Cooper, M. Irestedt, J. Jackson, U. S. Johansson, J. A. Norman: A Gondwanan origin of passerine birds supported by DNA sequences of the endemic New Zealand wrens. In: Proceedings of the Royal Society of London Series B. Band 269, Nr. 1488, 2002, S. 235–241, doi:10.1098/rspb.2001.1877, PMC 1690883 (freier Volltext).
F. Keith Barker, Alice Cibois, Peter Schikler, Julie Feinstein, Joel Cracraft: Phylogeny and diversification of the largest avian radiation. In: PNAS. Band 101, Nr. 30, Juli 2004, Artikelnummer 11040–11045, doi:10.1073/pnas.0401892101 (PDF).
nih.gov
ncbi.nlm.nih.gov
P. G. P. Ericson, L. Christidis, A. Cooper, M. Irestedt, J. Jackson, U. S. Johansson, J. A. Norman: A Gondwanan origin of passerine birds supported by DNA sequences of the endemic New Zealand wrens. In: Proceedings of the Royal Society of London Series B. Band 269, Nr. 1488, 2002, S. 235–241, doi:10.1098/rspb.2001.1877, PMC 1690883 (freier Volltext).
nre.tas.gov.au
Zitat: Passerines are known as perching birds because of the shape of their feet: all passerines have three toes pointing forward and one back with ligaments arranged so that the foot locks on to a perch when the bird perches or sleeps.Lots of non-passerines have three toes forward and one back, but they are shaped differently to those of passerines to suit their particular lifestyle. For example, swans, ducks and gulls have webbed feet; cormorants and pelicans have totipalmate feet (i.e. with all four toes connected by webbing); wading birds usually have long toes. Sarah Loyd: Bugs, birds, bettongs & bush (PDF; 3,8 MB), Seite 19, 2003.
pnas.org
F. Keith Barker, Alice Cibois, Peter Schikler, Julie Feinstein, Joel Cracraft: Phylogeny and diversification of the largest avian radiation. In: PNAS. Band 101, Nr. 30, Juli 2004, Artikelnummer 11040–11045, doi:10.1073/pnas.0401892101 (PDF).
