852 1st Indicator 1 - Dewey Decimal classification:

Value 1 indicates that the item is shelved by a Dewey Decimal Classification number. This number, which is contained in subfield $h (Classification part), is assigned from the Dewey Decimal Classification and Relative Index, the Abridged Dewey Decimal Classification and Relative Index, or the DC&: Dewey Decimal Classification Additions, Notes and Decisions. These three publications are maintained by the Library of Congress. A full description of a Dewey Decimal classification is given under field 082 (Dewey Decimal Call Number).