Pohll, G. M., Carroll, R. W., Reeves, D. M., Parashar, R., Muhunthan, B., Thyiyagarjah, S., Badger, T., Lowell, S., Willoughby, K. (2013). Design Guidelines for Horizontal Drains Used for Slope Stabilization: Washington State Department of Transportation Report, WA-RD 787.1