TY  - BOOK
AU  - Harrison,Hal H.
TI  - A field guide to western birds'nests of 520 species found breeding in the United States west of the Mississippi river
T2  - The Peterson field guide series
SN  - 0-395-27629-2
AV  - QL675 H37
PY  - 1979///
N1  - Incluye bibliografia
ER  -