Murphy, D. and Harshman, W. (2007) Horizontal silo safety. The Pennsylvania State University College of Agricultural Sciences. Retrieved from https://extension.psu.edu/horizontal-silo-safety.

Murphy, D. and Harshman, W. (2007) Horizontal silo safety. The Pennsylvania State University College of Agricultural Sciences. Retrieved from https://extension.psu.edu/horizontal-silo-safety.acs-admin2022-10-07T14:46:48+00:00