@unpublished{Duncan2000,
author = {Alan Duncan and Graham Stark},
title = {A recursive algorithm to generate piecewise linear budget contraints},
year = {2000},
month = {May},
volume = {pp},
doi = {10.1920/wp.ifs.2000.0011},
issn = {1742-0415},
url = {http://www.ifs.org.uk/wps/wp0011.pdf},
}