Birkby, Jeff (January 2016). "Vertical Farming". ATTRA Sustainable Agriculture Program. Archived from the original on 11 February 2016. Retrieved October 28, 2019. منبع : هاوین الکترونیک
Birkby, Jeff (January 2016). "Vertical Farming". ATTRA Sustainable Agriculture Program. Archived from the original on 11 February 2016. Retrieved October 28, 2019. منبع : هاوین الکترونیک
Birkby, Jeff (January 2016). "Vertical Farming". ATTRA Sustainable Agriculture Program. Archived from the original on 11 February 2016. Retrieved October 28, 2019. منبع : هاوین الکترونیک