Kunkel, J. R., Murphy, W. M., Rogers, D. and Dugdale, Jr., D. T. (1983) “Seasonal control of gastrointestinal parasites among dairy heifers using two strategically timed treatments of fenbendazole”, The Bovine Practitioner, 1983(18), pp. 54–57. doi: 10.21423/bovine-vol1983no18p54-57.