An account of the assassination of loyal citizens of North Carolina, for having served in the Union Army, which took place at Kingston in the months of February and March, 1864 / by Rush C. Hawkins. (OCLC #993606950)

This volume includes this ISBN statement on the title page verso:

    ISBN: 4444000055732PB

though only the digits appear in the book’s barcode.

An ISBN is considered to be structurally invalid when “its length or structure is incorrect or its check digit does not agree with the formula for calculating it.” This one has 13 digits, and the final digit DOES match what would be computed by the check digit formula:

    (4 + 3*4 + 4 + 3*4 + 0 + 3*0 + 0 + 3*0 + 5 + 3*5 + 7 + 3*3
         + digit) mod 10 = 0
      (68 + digit) mod 10 = 0
      digit = 2
         

But it is otherwise not structurally correct; in particular, it does not start with a GS1 ISBN prefix (978 or 979).

Such ISBNs are still recorded in the 020 field in MARC, but in ǂz instead of ǂa:

    020 __ ǂz 4444000055732