1. National Farm Medicine Center, Marshfield Clinic Research Institute (MCRI), Marshfield, Wisconsin, USA
2. Department of Agricultural & Biological Engineering, Penn State University, University Park, Pennsylvania, USA
3. Department of Economics, Colorado State University and Colorado School of Public Health, Fort Collins, Colorado, USA
4. National Children’s Center for Rural and Agricultural Health and Safety, Marshfield Clinic Research Institute (MCRI), Marshfield, Wisconsin, USA