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- Cărți electroniceScience and Happiness (translated)Georges Lakhovsky
- Cărți electroniceLa nature et ses merveilles (traduit)Georges Lakhovsky
- Cărți electroniceScience et bonheur (traduit)Georges Lakhovsky
- Cărți electroniceNaturaleza y sus maravillas (traducido)Georges Lakhovsky
- Cărți electroniceNatur und seine wunder (übersetzt)Georges Lakhovsky
- Cărți electroniceWissenschaft und Glück (übersetzt)Georges Lakhovsky
- Cărți electroniceCiencia y felicidad (traducido)Georges Lakhovsky