Bickel, A. F.; Gaasbeek, C. J.; Hogeveen, H.; Oelderik, J. M.; Platteeuw, J. C. (). „Chemistry and spectroscopy in strongly acidic solutions: reversible reaction between aliphatic carbonium ions and hydrogen”. Chemical Communications. 1967: 634–5. doi:10.1039/C19670000634.Mentenanță CS1: Nume multiple: lista autorilor (link)
Hogeveen, H.; Bickel, A. F. (). „Chemistry and spectroscopy in strongly acidic solutions: electrophilic substitution at alkane-carbon by protons”. Chemical Communications. 1967: 635–6. doi:10.1039/C19670000635.Mentenanță CS1: Nume multiple: lista autorilor (link)