Meltzoff and Moore- 1977

Isabella et al- 1989

Klaus and Kennell- 1976

Crotwell et al- 2013

Feldman- 2012

Bowlby- 1969

Bowlby (2)- 1969

Field- 1978

Grossman- 2002

Pederson- 1979

Grossman- 2002 (2)

Guiton- 1966

Howe- 1998

Sackett- 2002

Schaffer and Emerson- 1964

Brazleton et al- 1975

Bailey et al- 2007

Kagan- 1982

Schaffer and Emerson- 1964 (2)

Hay and Vespo- 1988

Main and Solomon- 1986

Takahashi- 1990

Bick et al- 2012