Authors: VAN DER VLERK I M DE BOCK J F SIROTTI A

Citation: M. Van Der Vlerk I et al., Biometrical investigations on Operculina and Lepidociclina. A test on their degree of objectivity and reliability for geological age and determinations, Bollettino della Societa paleontologica italiana , 11(01), 1972, pp. 86-99