On the advice of the prominent Utrecht natural historian Pieter Harting, he applied a numerical system in which the fossils were divided into Periods (Paleozoic, Mesozoic and Caenozoic) and sorted from 'high' to 'low'.
Tiberius | Henry Winkler | Tiberius Gracchus | Cornelis Johannes van Houten | Cornelis Tromp | Cornelis de Bie | Winkler, Manitoba | Winkler | Tiberius Sempronius Gracchus | Cornelis Vreeswijk | Winkler test for dissolved oxygen | Jacob Cornelis Matthieu Radermacher | Tiberius Claudius Narcissus | Tiberius Claudius Cogidubnus | Scott Winkler | Irwin Winkler | Cornelis Matelief de Jonge | Cornelis Kruseman | Cornelis Johannes Kieviet | Cornelis de Bruijn | Angela Winkler | ''William Fitzwilliam, Second Lord Fitzwilliam of Liffer'', Cornelis Janssens van Ceulen | Warren Winkler | Tiberius Junius Brutus | Tiberius Julius Pollienus Auspex | Tiberius Julius Cotys I | Tiberius Julius Alexander | Tiberius Canutius | Pieter Cornelis Dommersen | Pieter Cornelis Boutens |