H. Hooyberghs and K. Wouters 2004. Marine Miocene deposits in the Maaseik well 49W/220 in eastern Belgium: biostratigraphy by means of various microfossil groups. Netherlands Journal of Geosciences. 83, (Mar. 2004), 33-40. DOI:https://doi.org/10.1017/S0016774600020448.