>  https://github.com/lcnetdev/marc2bibframe/blob/master/python/lib/marc.py. Anyone experiencing a sleepless night should consider this task :-).


Again, interesting.

Many MARC fields and subfields are not named, e.g.:

All fixed fields 
016 (vital for Canadian libraries) 
055 (vital for Canadian libraries) 
060 (vital for medical libraries) 
070 (vital for agricultural libraries) 
080 (important for some European libraries)
OCLC's 090, 092
210 
222 
(but seldom used 243 is included) 
245$h 
247
264
336
337
338 
440, 400, 410, 411, 503 (although obsolete, they exist in records) 
All 5XX notes seem undifferentiated except 505, 520, and 521, making a 
  walk back to MARC impossible.
506
538
540
546
611
77X 
78X
800
810
811
830 
etc.

These missing fields are just those we have used, or often use,
without reference to MARC21 fields given in documentation, which are 
*much* more extensive.

So far, this seems a *very* dumbed down conversion, lacking information
important to our clients.


   __       __   J. McRee (Mac) Elrod ([log in to unmask])
  {__  |   /     Special Libraries Cataloguing   HTTP://www.slc.bc.ca/
  ___} |__ \__________________________________________________________