1. “Foramines: The Geothermal Drilling Contractor”, Brochure 606.88.26, Paris, France, undated.
2. Handbook of Geothermal Energy,1982
3. PNOC Energy Drilling, Inc., PNOC Rig No. 4, National 610, Metro Manila, Philippines, undated.
4. “What to Consider When Selecting Drilling Fluids”;Hutchison,1974
5. “Geothermal Cementing”;Shyrock,1982