Publication Found
- Bulletin 232--Biostratigraphy of Middle and Late Pennsylvanian (Desmoinesian-Virgilian) Ammonoids
 - by D. R. Boardman , D. M. Work , R. H. Mapes , J. E. Barrick
 - 121 p., 1994, $10.00
 - Abstract available online
 - Full Version available online