Gaya APA

Susanto, A., Vonbun, F. (1981). Earth's gravity field mapping requirements and concept . Washingthon: National Aeronautics and Space Administration.

Gaya MLA

Susanto, Al., Vonbun, F.O.. "Earth's gravity field mapping requirements and concept". Washingthon: National Aeronautics and Space Administration, 1981. Text.