Robert J Willis

Critical path analysis and resource constrained project scheduling -- Theory and practice

Robert J Willis, 1985 .

Prevalence of Cognitive Impairment without Dementia in the United States

Steven G Heeringa, John J McArdle, Robert B Wallace, 2008, Annals of Internal Medicine.

Informal caregiving for diabetes and diabetic complications among elderly americans.

Rodney A Hayward, Robert J Willis, Mohammed U Kabeto, 2002, The journals of gerontology. Series B, Psychological sciences and social sciences.