Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:…coefficient)
CDa ¼ Zh
0
PADðzÞ uðzÞ 2
u0w0ð42 mÞ dz
0
@
1
A
1
ð10Þ
Both of the methods give plausible results (for the west wind sector: CD ¼ 0:130 and CDa ¼ 0:132) and they are very close to the values found in literature (e.g. Amiro 1990; Kerzenmacher and Gardiner 1998; Pinard and Wilson 2001).
Category: