[1]Lưu trữ 2018-06-01 tại Wayback Machine Bertschinger, L. et al. (eds) (2004). Conclusions from the 1st Symposium on Sustainability in Horticulture and a Declaration for the 21st Century. In: Proc. XXVI IHC – Sustainability of Horticultural Systems. Acta Hort. 638, ISHS, pp. 509-512. Truy cập: 2009-03-16.
[1]Lưu trữ 2018-06-01 tại Wayback Machine Bertschinger, L. et al. (eds) (2004). Conclusions from the 1st Symposium on Sustainability in Horticulture and a Declaration for the 21st Century. In: Proc. XXVI IHC – Sustainability of Horticultural Systems. Acta Hort. 638, ISHS, pp. 509-512. Truy cập: 2009-03-16.