PUIA, Ioan, Vasile SORAN, and Eugenia CHIRCA. “The Position of Agricultural Ecosystems Among the Ecosystems of Contemporary Biosphere and Their Productivity”. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 25, no. 1 (August 5, 1995): 99-108. Accessed October 19, 2021. https://www.notulaebotanicae.ro/index.php/nbha/article/view/319.