VALKÓ, László; KISS, András. ECO-LABELS IN HUNGARIAN PUBLIC PROCUREMENT. Periodica Polytechnica Social and Management Sciences, [S. l.], v. 13, n. 2, p. 107–120, 2005. Disponível em: https://pp.bme.hu/so/article/view/1646. Acesso em: 16 jun. 2025.