Natuurhistorisch Maandblad

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Natuurhistorisch Genootschap Limburg

J. Hofker. (1961). Foraminifera from the Cretaceous of South-Limburg, Netherlands: LII. Stratigraphy of the Gulpen Chalk in South-Limburg, established by means of the orthogenesis of Bolivinoides. Natuurhistorisch Maandblad, 50(3/4), 37–41.