Hi Brad. I looked for an example of an accession number for microfiche, as used in a marc record, and found the following example: (The accession number is 05000, found in fields 490 and 830, pretty much as you had suggested.) 000 00858nam 2200181 a 450 001 571327 008 810528c19801898enka b 00011 eng 0 020 __ |a 0665050003 (Positive copy) 035 __ |a (CaOOCIHM)81603284X 035 __ |9 ACN8054TS 040 __ |a CaOOCIHM |b eng 100 10 |a Allen, Grant, |d 1848-1899 245 13 |a An African millionaire |h [microform] : |b episodes in the life of the illustrious Colonel Clay / |c by Grant Allen. 260 0_ |a London : |b G. Richards, |c 1898. 300 __ |a 4 microfiches (183 fr.) : |b ill. 490 1_ |a CIHM/ICMH Microfiche series = CIHM/ICMH collection de microfiches ; |v no. 05000 533 __ |a Filmed from a copy of the original publication held by the Izaak Walton Killam Mmemorial Library, Dalhousie University. |b Ottawa : |c Canadian Institute for Historical Microreproductions, |d 1980. 830 _0 |a CIHM/ICMH Microfiche series ; |v no. 05000 Thanks, Andrew