APA
Federation International Des Geometres, .Sixteenth international congress of surveyors, Montreux, 9-18th August 1981. : .
Chicago
Federation International Des Geometres, .Sixteenth international congress of surveyors, Montreux, 9-18th August 1981. : .
Harvard
Federation International Des Geometres, .Sixteenth international congress of surveyors, Montreux, 9-18th August 1981. : .
MLA
Federation International Des Geometres, .: . .