LETTERS OF EULER ON DIFFERENT SUBJECTS IN NATURAL PHILOSOPHY (BREWSTER, DAVID/EULER, LEONHARD/GRISCOM, JOHN)
LETTERS OF EULER TO A GERMAN PRINCESS, ON DIFFERENT SUBJECTS IN PHYSICS AND PHIL (HUNTER, HENRY/DE CONDORCET, JEAN-ANTOINE-NICOLAS CARIT/EULER, LEONHARD)
CARTAS A UNA PRINCESA DE ALEMANIA SOBRE DIVERSOS TEMAS DE FÍSICA Y FILOSOFÍA (MINGUEZ PEREZ, CARLOS/EULER, LEONHARD)