Gaya APA

Service, P, E., Contra, I, A, O, D. (1968). Lessons in rotary drilling. Unit II Lesson 3. drilling a straight hole. (1968). : Texas : Petroleum Extension Service (PETEX),.

Gaya MLA

Service, Petroleum, Extension., Contra, Inter., Ass., Of, Drilling. "Lessons in rotary drilling. Unit II Lesson 3. drilling a straight hole.". 1968 : Texas : Petroleum Extension Service (PETEX),, 1968. Text.