1. What Are Key Factors to Consider When Installing Large Butterfly Valves Belowground?. Issue 10 (1st October 2017) Authors: Ballun, John V.; Holstrom, John R. Journal: Opflow Issue: Volume 43:Issue 10(2017) Page Start: 6 Record Type: Journal Article View Content: Available online (eLD content is only available in our Reading Rooms) ↗