1. Oil Well Drilling Technology;McCray,1959
2. API Specification for Steel Derricks;American Petroleum Institute (API) Standard 4A,1967
3. API Specification for Portable Masts;API Standard 4D,1967
4. Specification for Drilling and Well Servicing Structures;API Standard 4E,1988
5. Specification for Drilling and Well Servicing Structures;API Standard 4F,1995