1)http://www.42explore.com/snake.htm
2)http://www.emasherbs.com/TEAS/bl-circulation.htm
3)http://brp.arc.nasa.gov/Science/Y_GBL/bsc_resrch.html#grav_what
4) Scientific American Magazine December 1988 P.92- 98
5) Anatomical position of heart in snakes with vertical orientation: a new hypothesis. Badeer HS. Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, NE, 68178-0224 , USA. http://www.ncbi.nlm.nih.gov/entrez/query
6) Gravity, blood circulation, and the adaptation of form and function in lower vertebrates. Lillywhite HB. Department of Zoology, University of Florida, Gainesville 32611, USA http://www.ncbi.nlm.nih.gov/entrez/query
7) Independent effects of heart-head distance and caudal blood pooling on blood pressure regulation in aquatic and terrestrial snakes. Seymour RS, Arndt JO. Environmental Biology, University of Adelaide, Adelaide, SA 5005, Australia. roger.seymour@adelaide.edu.au http://www.ncbi.nlm.nih.gov/entrez/query
8) Blood flow uphill and downhill: does a siphon facilitate circulation above the heart? Seymour RS, Johansen K. Department of Zoology, University of Adelaide, South Australia. http://www.ncbi.nlm.nih.gov/entrez/query
9) http://spacephysiology.arc.nasa.gov/projects/snakes.html
10)http://www.critterridders.com/snake_info.htm
11)http://www.fda.gov/fdac/features/995_snakes.html
12)http://www.newscientist.com/news/news.jsp?id=ns99993232
13)http://www.allanstime.com/UnifiedFieldTheory/gravity.htm
14)http://www.iuk.indiana.edu/faculty/mfinkler/p416/circulation.htm
15)http://www.spiritual-teachers.com/AmazingScience.htm
16)http://sln.fi.edu/biosci/vessels/vessels.html
17)http://www.sunburst-traders.com/BlodCirc.htm
18)http://www.pestcontrol-products.com/snake_info.htm
19)http://www.rccd.cc.ca.us/library/rivcirc.htm
20)http://www.suzannes.com/glosofter.html