- Author: Peter H. Raven (editor), Ray F. Evert (editor), Helena Curtis (editor), Rosemarie Langenfeld-Heyser (editor)
- Language: German
- Year: 1985
Biologia
pdf
- Author: Helena Curtis
- Language: Spanish
- Year: 1977
Biología
pdf
- Author: Helena Curtis, N. Sue Barnes, Adriana Schnek, Alicia Massarini
- Language: Spanish
- Year: 2008
Biología
pdf
- Author: Helena Curtis Sue Barnes Adriana Schnek
- Language: Spanish
- Year: 2008
