CL Classes

a2 in cl

fermentation in cl

The CL field contains both codes and section names classifying the focus or the context of the record, such as genetic engineering, agriculture, and pharmaceuticals.

Some class and section names changed in January 1993; the following codes have different meanings post-January 1993: D3, E2, G1, H2, H3. If you wish to limit your search to pre-1993 records, add and ay<93 to your search; to limit your search to post-1992 records, add and ay>92.