Link to Journal Article on Declining Union Densities and Lower Wages in US

You will have to purchase this article, but for those looking for scholarly research on the connection between the decline of union density and lower wages, this piece in the American Sociological Review will be useful. The abstract explains how Western and Rosenfeld "argue that unions helped institutionalize norms of equity, reducing the dispersion of nonunion wages in highly unionized regions and industries. Accounting for unions’ effect on union and nonunion wages suggests that the decline of organized labor explains a fifth to a third of the growth in inequality—an effect comparable to the growing stratification of wages by education."