@unpublished{Griffith2001,
author = {Rachel Griffith},
title = {Product market competition, efficiency and agency costs: an empirical analysis},
year = {2001},
month = {May},
volume = {pp},
doi = {10.1920/wp.ifs.2001.0112},
issn = {1742-0415},
url = {http://www.ifs.org.uk/wps/wp0112.pdf},
}