001 (records from OCLC)
035 (records from other sources)
For a history of the OCLC number, please refer to OCLC's Technical Bulletin No 253.
Take the first matching field found (thus 001 takes precedence over 035).
Leading zeroes and prefxes are ignored during comparison.
Each OCLC number is queried three different ways ('n' is a non-zero digit):
Matching stops if the number of records retrieved exceeds 'Max Numeric Hits'