1Dr. Kenneth M. Langa MD, PhD,Michael E. Chernew PhD,Mohammed U. Kabeto MS,A. Regula Herzog PhD,Mary Beth Ofstedal PhD,Robert J. Willis PhD,Robert B. Wallace MD,Lisa M. Mucha PhD,Walter L. Straus MD, MPH,A. Mark Fendrick MD. National estimates of the quantity and cost of informal caregiving for the elderly with dementia[J] 2001,Journal of General Internal Medicine(11):770~778