DE SWARDT, D. H. Observations on a Secretarybird nest at Langfontein, Petrusburg district, Free State. Biodiversity Observations, [S. l.], v. 7, p. 1–4, 2016. Disponível em: https://journals.uct.ac.za/index.php/BO/article/view/357. Acesso em: 4 jul. 2022.