एपीए उद्धरण

Piedra Constantino, R. d. l. (1997). Evaluation of sustainable production systems in hillsides, La Fraylesca, Chiapas, México.

शिकागो स्टाइल उद्धरण

Piedra Constantino, R. de la. Evaluation of Sustainable Production Systems in Hillsides, La Fraylesca, Chiapas, México. 1997.

एमएलए उद्धरण

Piedra Constantino, R. de la. Evaluation of Sustainable Production Systems in Hillsides, La Fraylesca, Chiapas, México. 1997.