Seminar on Regional Planning and Regional Government in Europe, Prague, & Kalk, E. (1971). Regional planning and regional government in Europe: Report of a symposium held in April 1969 in Prague, Czechoslovakia. International Union of Local Authorities.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Seminar on Regional Planning and Regional Government in Europe, Prague, و E. Kalk. Regional Planning and Regional Government in Europe: Report of a Symposium Held in April 1969 in Prague, Czechoslovakia. [The Hague: International Union of Local Authorities, 1971.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Seminar on Regional Planning and Regional Government in Europe, Prague, و E. Kalk. Regional Planning and Regional Government in Europe: Report of a Symposium Held in April 1969 in Prague, Czechoslovakia. International Union of Local Authorities, 1971.