Mölder, H. Foreword // Department of Environmental Engineering : activity report 1998. Tallinn : TTÜ kirjastus, 1999. p. 4. (Reports of Tallinn Technical University. F, Civil engineering = Tallinna Tehnikaülikooli ülevaated. F, Civil engineering = Отчеты Таллинского технического университета. F, Civil engineering ; 6). https://www.ester.ee/record=b1236017*est