ted for tables that do not contain the variable, and names should be ordered in the same order of the tables that are being merged (i.e. the first column name should be present in the first table being merged). The name of the merged columns can be modified by assigning a name to the elements of the list. For example, <code>list("countries"=c("Nation",NA,"COUNTRY"), "sector"=c("Industry","industry",NA))</code> is requesting to merge the columns <code>tab1$Nation</code> and <code>tab3$COUNTRY</code>, and the