Perhaps you should try some spelling variations:
"coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicat des cheminots" » "coöperatie/vakbonden van de spoorwegarbeiders | coopération/syndicat des cheminots", "coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicaat des cheminots", "coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicale des cheminots"
"coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicats des cheminots" » "coöperatie/vakbonden van de spoorwegarbeiders | coopération/syndicats des cheminots", "coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicaats des cheminots", "coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicales des cheminots", "coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicale des cheminots", "coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicaat des cheminots"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicat des cheminots\") OR (\"coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicats des cheminots\"))~".
• Removing quotes may allow a broader search: (( coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicat des cheminots ) OR ( coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicats des cheminots ))~.
• Adding a wildcard symbol may retrieve word variants: (("coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicat des cheminots") OR ("coöperatie/vakbond van de spoorwegarbeiders | coopération/syndicats des cheminots"))*.