RT Journal T1 Surgeon general's workshop on health promotion and aging: Summary recommendations of physical fitness and exercise working group JF JAMA JO JAMA YR 1989 FD November 10 VO 262 IS 18 SP 2507 OP 2510 DO 10.1001/jama.1989.03430180033007 UL http://dx.doi.org/10.1001/jama.1989.03430180033007 AB