Errickson Sadye Paez, Alvarez Mayra, Forquera Ralph, Whitehead Tony L, Fleg Anthony, Hawkins Tracey, Browne Dorothy C, Newsom M Cookie, Schoenbach Victor J
School of Medicine, Division of Physical Therapy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7135, USA.
Public Health Rep. 2011 Mar-Apr;126(2):170-5. doi: 10.1177/003335491112600207.