Affiliations Research 1987[position unknown]Pennsylvania School Of Medicine1985[position unknown]University Of Pennsylvania School Of Medicine1986[position unknown]University Of Pennsylvania School Of Medicine1984[position unknown]University Of Pennsylvania1989[position unknown]University Of Pennsylvania 1984[subject unknown]Library Readers1985[subject unknown]Library Readers1986[subject unknown]Library Readers1987[subject unknown]Library Readers1989[subject unknown]Library Readers