TY  - CHAP
A1  - Euler, H.A.
A1  - Michalski, R.L. 
T1  - Grandparental and extended kin relationshps
Y1  - 2008
A3  - Salmon, C.A.
A3  - Shackelford, T.K.
T2  - Family relationships: An evolutionary perspective
CY  - New York
PB  - Oxford University Press

ER  -