Groh, H. (1942). Hackberry in the Ottawa District. Zenodo.
Cita Chicago (17th ed.)Groh, Herbert. Hackberry in the Ottawa District. Zenodo, 1942.
Cita MLA (9th ed.)Groh, Herbert. Hackberry in the Ottawa District. Zenodo, 1942.
Atenció: Aquestes cites poden no estar 100% correctes.