http://www.agclassroom.org/gan/timeline/crops_livestock.htm http://www.agclassroom.org/gan/timeline/crops_livestock.htm http://www.agclassroom.org/gan/timeline/crops_livestock.htm A History of American Agriculture: Crops and Livestock Crops & Livestock http://www.agclassroom.org/gan/timeline/crops_livestock.htm http://www.agclassroom.org/gan/timeline/crops_livestock.htm http://www.agclassroom.org/gan/timeline/crops_livestock.htm "Historical Timeline — Crops & Livestock" http://www.agclassroom.org/gan/timeline/crops_livestock.htm http://www.agclassroom.org/gan/timeline/crops_livestock.htm