@misc{Racioppi2002,
author = {Racioppi, F. and Rivellini, G.},
title= {The contextual dimension in GGP: Some methodological issues about data collection and sampling procedures},
year = {2002},
URL = {http://www.unece.org/fileadmin/DAM/pau/_docs/ggp/2003/GGP_2003_IWG002_BgDocCDBWG.pdf},
}