9American Petroleum Institute. Recommended Practice on the Rheology and Hydraulics of Oil-well Drilling Fluids, API RP 13D Fourth Edition[Z]. The American Petroleum Institute, 2003.
10American Petroleum Institute. Recommended Practice on the Rheology and Hydraulics of Oil-well Drilling Fluids, API RP 13D Third Edition[Z]. The American Petroleum Institute, 2003.