Gaya APA

Service, P, E., Contra, I, A, O, D. (1969). Lessons in rotary drilling. Unit III Lesson 1. controlled directional drilling. (1969). : Texas : Petroleum Extension Service (PETEX),.

Gaya MLA

Service, Petroleum, Extension., Contra, Inter., Ass., Of, Drilling. "Lessons in rotary drilling. Unit III Lesson 1. controlled directional drilling.". 1969 : Texas : Petroleum Extension Service (PETEX),, 1969. Text.