Questo Link non esiste nella tua lingua, Vedi in: English (en),
Oppure utilizzare Google Translate:  

https://attra.ncat.org/

ATTRA is a program developed and managed by the National Center for Appropriate Technology (NCAT). The majority of funding for ATTRA is through a cooperative agreement with the United States Department of Agriculture's Rural Business-Cooperative Service. We are also partially funded through sales and subscriptions of a portion of ATTRA materials and through contributions from friends and supporters. We are committed to providing high value information and technical assistance to farmers, ranchers, Extension agents, educators, and others involved in sustainable agriculture in the United States