1970  Pfefferkorn, H.W.  Use of plant megafossils in correlation of the Pennsylvanian of the Illinois Basin with the Upper Carboniferous of Europe.Geological Society of America, Abstracts with Programs, v. 2, no. 7, p. 652 (Abstr.)

1971  Rao, C.P. & H.W. Pfefferkorn.  Occurrence and mineralogy of coal balls in the Illinois Basin.  Geological Society of America, Abstracts with Programs, v. 3, p. 678 (Abstr.)

1974  Pfefferkorn, H.W.  The compression flora of the McLeansboro Group (Upper Pennsylvanian) of Illinois.  Geological Society of America, Abstracts  with Programs, v. 6, no. 7, p. 1055 (Abstr.)

1979  Resnik, D.A. & H.W. Pfefferkorn.  Revision of the genus Odontopteris  from the Pennsylvanian of North America.  9th International Congress of Carboniferous Stratigraphy and Geology, Abstracts of Papers, p. 179 (Abstr.)

1979  Scheihing, M.H. & H.W. Pfefferkorn.  Ecologic and taxonomic implications of morphologic variation in Carboniferous pteridosperm foliage.  9th International Congress of Carboniferous Stratigraphy and Geology, Abstracts of Papers, p. 194-195 (Abstr.)

1985  Pfefferkorn, H.W.  Contribution of terrestrial vegetation to the marine food chain and marine sedimentation in front of tropical deltas.  Terra cognita, 5(1), p. 79 (Abstr.)

1989  Pfefferkorn, H.W. & V. Alleman.  New Climatic Belt in Carboniferous of Southern Hemisphere.  28^th International Geological Congress, Washington, DC, Abstracts, v. 2, p. 602 (Abstr.)

1994  Yemane, K. & H.W. Pfefferkorn.  Signatures of Pennsylvanian climates in the clay mineral assemblages of the Appalachian basin.  Geological Society of America, Abstracts with Programs, v. 24, no. 7, p. A-216 (Abstr.)

1995  Pfefferkorn, H.W. & Thomas Wagner.  Coastal transgression over peat environments in a generally progradational setting (Orinoco Delta, Venezuela).  Geological Society of America, Abstracts with Programs, v. 27, no. 7, p. A 31  (Abstr.)

1997  Iannuzzi, R., Guerra-Sommer, M., & H.W. Pfefferkorn.  Phytogeographic considerations on the origin of the Glossopterideae.  Revista Universidade Guarulhos, Geociências II, Numero Especial, p. 226 (Abstr.)

1999  Pfefferkorn, H.W.  Paleobiogeography and biostratigraphy of the Pennsylvanian floras from the Narragansett Basin: A review.  Geological Society of America, Abstracts with Programs, v. 31, no. 2, p. A-60 (Abstr.)

1999  Pfefferkorn, H.W., LePage, B.A. & Gillespie, W.H.  An Isoetalean lycopsid from the margin of the Greenbrier-Bluefield sea (Late Mississippian) of Virginia.  Abstracts XIV International Congress on the Carboniferous-Permian, p. 114 (Abstr.).

2006 Kotasowa, A., Kotas, A., & Pfefferkorn, H.W.  Floristic turn-over and stability in the Namurian (Serpukhovian-lower Bashkirian) of the Upper Silesian Coal Basin (Poland) as an indicator of paleoclimatic change in the mid-Carboniferous tropics. Geological Society of America, Abstracts with Programs, v. 38, no. 7, p. 316 (Abstr.).

2006 Migier, T., Zdanowski, A., & Pfefferkorn, H.W.  Climatic signal in the tropics based on plant-taphonomy during early stages of the Carboniferous icehouse interval (Namurian, Lublin Basin, Poland). Geological Society of America, Abstracts with Programs, v. 38, no. 7, p. 316 (Abstr.).

2014 Pfefferkorn, H.W.  Roots are often not traces and need a terminology different from animal ichnofossils.  Geological Society of America Abstracts with Programs, v. 46(2), p. 77.