Gaya APA

Surveyors, I, F, O. (1990). XXI Congress: International Federation of Surveyor Helsinki Finland 10-19 June 1990 . Helsinki: International Federation of Surveyor.

Gaya MLA

Surveyors, International, Federation, Of. "XXI Congress: International Federation of Surveyor Helsinki Finland 10-19 June 1990". Helsinki: International Federation of Surveyor, 1990. Cetak.