TY  - SER
AU  - Cowan, Frank L.
TI  - More on estimating tillage effects : : reply to dunnll and yorston
T2  - American Antiquity ; 
PY  - 1990///
CY  - Washington-US : 
PB  - Society for American Archaeology, 
N1  - Artículo dentro de: Comments
ER  -