* Carl F. Jordan, [https://books.google.co.il/books?id=tWRGAAAAQBAJ&pg=PA34&lpg=PA34&dq=Agricultural+productivity+EROI&source=bl&ots=Bu7tppyXK6&sig=TYXxbUwrZnJBdHt3j196bVLOO<sub>3</sub>U&hl=iw&sa=X&ei=PQfzVIrZL9HgaNWtgJgB&ved=0CDIQ6AEwAg#v=onepage&q=Agricultural%20productivity%20EROI&f=false An Ecosystem Approach to Sustainable Agriculture: Energy Use Efficiency in the American South] | * Carl F. Jordan, [https://books.google.co.il/books?id=tWRGAAAAQBAJ&pg=PA34&lpg=PA34&dq=Agricultural+productivity+EROI&source=bl&ots=Bu7tppyXK6&sig=TYXxbUwrZnJBdHt3j196bVLOO<sub>3</sub>U&hl=iw&sa=X&ei=PQfzVIrZL9HgaNWtgJgB&ved=0CDIQ6AEwAg#v=onepage&q=Agricultural%20productivity%20EROI&f=false An Ecosystem Approach to Sustainable Agriculture: Energy Use Efficiency in the American South] |