Lower Ordovician Trilobites of the Kirtonryggen Formation, SpitsbergenRichard A. Fortey, David L. Bruton · First published 2013Open the Tome
Early Ordovician (Arenig) stratigraphy and faunas of the Carmarthen district, south-west WalesRichard A. Fortey · First published 1978Open the Tome
The Ordovician trilobite Hadrohybus Raymond 1925, and its family relationships (Postilla)Richard A. Fortey · First published 1900Open the Tome