Untermann, R. K. (1973). Grade easy: An introductory course in the principles and practices of grading and drainage. Landscape Architecture Foundation.
Цитирование в стиле Чикаго (17-е изд.)Untermann, Richard K. Grade Easy: An Introductory Course in the Principles and Practices of Grading and Drainage. Vienna, Va: Landscape Architecture Foundation, 1973.
Цитирование MLA (9-е изд.)Untermann, Richard K. Grade Easy: An Introductory Course in the Principles and Practices of Grading and Drainage. Landscape Architecture Foundation, 1973.
Предупреждение: эти цитированмия не могут быть всегда правильны на 100%.