Köpke, G., & Grundheber-Pilgram, A. (1990). The centenary of May Day ; Portrait of the European Trade Union Confederation (ETUC). Brussels: ETUI.
芝加哥风格引文Köpke, Günter, 与 Alfons Grundheber-Pilgram. The Centenary of May Day ; Portrait of the European Trade Union Confederation (ETUC). Brussels: ETUI, 1990.
MLA引文Köpke, Günter, 与 Alfons Grundheber-Pilgram. The Centenary of May Day ; Portrait of the European Trade Union Confederation (ETUC). Brussels: ETUI, 1990.
警告：这些引文格式不一定是100％准确.