อ้างอิง ของ หงส์แตร

  1. ↑ BirdLife International (2012). "Cygnus buccinator". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. สืบค้นเมื่อ 17 July 2012.CS1 maint: ref=harv (link)
  2. 1 2 3 4 Madge, Steve; Burn, Hilary (1988). Waterfowl: An Identification Guide to the Ducks, Geese, and Swans of the World. Boston: Houghton Mifflin. ISBN 0-395-46727-6.
  3. 1 2 Mute Swan, Cornell Lab of Ornithology. Retrieved on 2011-12-18.
  4. 1 2 Ogilvie, M. A.; Young, S. (2004). Wildfowl of the World. New Holland Publishers. ISBN 978-1-84330-328-2.
  5. ↑ "Trumpeter Swan, Life History, All About Birds". Cornell Lab of Orinthology. สืบค้นเมื่อ 2012-06-22.
  6. ↑ "Arkive – Trumpeter Swan video, photos and facts". Arkive: Images of Life on Earth. สืบค้นเมื่อ 2012-06-21.
  7. ↑ Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats. ISBN 978-0-85112-235-9.
  8. ↑ Squires, J.R. and Anderson, S.H. (1997). "Changes in trumpeter swan (Cygnus buccinator) activities from winter to spring in the greater Yellowstone area". American Midland Naturalist. 138 (1): 208–214. doi:10.2307/2426667. JSTOR 2426667.CS1 maint: multiple names: authors list (link)

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WikiPedia: หงส์แตร http://ibc.lynxeds.com/species/trumpeter-swan-cygn... http://wolseleywildlife.com/ http://www.birds.cornell.edu/AllAboutBirds/BirdGui... http://www.beachwatchers.wsu.edu/island/images/Tru... http://www.mbr-pwrc.usgs.gov/id/framlst/i1810id.ht... http://www.allaboutbirds.org/guide/Trumpeter_Swan/... http://www.arkive.org/trumpeter-swan/cygnus-buccin... http://www.birdlife.org/datazone/species/index.htm... //doi.org/10.2307%2F2426667 http://www.iucnredlist.org/apps/redlist/details/10...