1979 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1977 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1976 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1975 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1973 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1972 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1971 · Illinois State Geological Survey, Van Den Berg, Jacob, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)
1967 · Jacob Van Den Berg, T.F. Lawry, et al. · Illinois Digital Environment for Access to Learning and Scholarship (University of Illinois at Urbana-Champaign)