- Author: Robert J. Barro, Vittorio Grilli, Hans-Jürgen Ahrns
- Language: German
- Year: 1996
- Author: Robert J. Barro Vittorio Grilli Ramon Febrero
- Language: Spanish
- Year: 1997
- Author: Robert J. Barro Vittorio Grilli Ramon Febrero
- Language: Spanish
- Year: 1997
- Author: Robert Barro Vittorio Grilli (auth.)
- Language: English
- Year: 1994