SQL Server allows article names containing period, which is handy in the cases where you are replicating tables with the same name that are located in different schemas, eg 'Purchase.Orders' and 'Sales.Orders'. However, if you attempt to open Microsoft Replication Conflict Viewer to look at the conflicts, you'll get the following error message:
Column '<column name>' does not belong to table summary. (System.Data)
Due to this error, you cannot override winner/looser for merge conflicts if the article name contains period.