On Wednesday, June 19, 2013 9:48 AM, Karen Coyle wrote:
>So the actual meaning of the subfields is that the 050 $a$b is the LC "call number" (including the class number) and the second 050 $a is an "alternative class number" (?). None of what you provide is even hinted at in the MARC documentation -- which shows the pitfalls of working from that documentation. Is there somewhere that actual *practice* is documented?

G70 of Subject Cataloging Manual:  Shelflisting, #7 covers Alternate numbers [1]. I'm not sure if this has been updated in its replacement, Classification and Shelflisting Manual [2], but G70 is not listed at [3] as having been renumbered or deleted.

[1] http://www.itsmarc.com/crs/mergedProjects/scmshelf/scmshelf/g_70_input_of_lc_call_numbers_copy_statements_050_051_fields_shelf.htm
[2] http://www.loc.gov/cds/products/product.php?productID=16
[3] http://www.loc.gov/catdir/cpso/scmsl.html

I hope this helps,

Bryan Baldus
Senior Cataloger
Quality Books Inc.
The Best of America's Independent Presses
1-800-323-4241x402
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