On varieties of groups and their associated near-rings. Hanna Neumann — 1956 Mathematische Zeitschrift
Linked products and linked embeddings of groups. Hanna Neumann; James Wiegold — 1960 Mathematische Zeitschrift
Wreath products and varieties of groups. B.H. Neumann; Hanna Neumann; Peter M. Neumann Mathematische Zeitschrift