APA (7th ed.) Citation

Sorre, M. (1961). Alexandre de Humboldt, 1769-1859. [publisher not identified].

Chicago Style (17th ed.) Citation

Sorre, Maximilien. Alexandre De Humboldt, 1769-1859. Paris: [publisher not identified], 1961.

MLA (9th ed.) Citation

Sorre, Maximilien. Alexandre De Humboldt, 1769-1859. [publisher not identified], 1961.

Warning: These citations may not always be 100% accurate.