"PBC." A Dictionary of Nursing. Oxford University Press. 2008. Encyclopedia.com. 26 Dec. 2009 <http://www.encyclopedia.com>.
"PBC." A Dictionary of Nursing. Oxford University Press. 2008. Encyclopedia.com. (December 26, 2009). http://www.encyclopedia.com/doc/1O62-PBC.html
"PBC." A Dictionary of Nursing. Oxford University Press. 2008. Retrieved December 26, 2009 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-PBC.html