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DB / Metadata Management Program (MMP): Fundamentals of the NLM® Classification

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Types of Call Numbers used by NLM


  • NLM assigns classification numbers to all materials.
  • Since June 2010, shelflisting (i.e. cutter numbers and dates) is only provided for material that will be shelved in the Reference Collection or the History of Medicine Division (HMD)
  • NLM classes serial analytics with the serial call numbers W1 and W3. Serial analytics also carry an alternative subject call number provided by NLM for libraries wishing to class such publications by subject


Last Reviewed: April 16, 2021