‘Building up slaveries in ancient Italy and the central Sudan,’ in: S. Bernard, L. Mignone and D. Padilla Peralta (eds.), Making the middle republic: new approaches to Rome and Italy, 400-200 BCE, Cambridge University Press: Cambridge, forthcoming

[with Kyle Harper] ‘Roman slavery and the idea of slave society’, in: N. Lenski and C. M. Cameron (eds.), What is a slave society? The practice of slavery in global perspective, Cambridge University Press: New York, 2018, 86-105

[ed. with John Bodel] On human bondage: after Slavery and social death, Wiley-Blackwell: Malden MA, Oxford and Chichester, 2017. XIV + 314 p.

‘Slavery and forced labor in early China and the Roman world’, in: H. J. Kim, F. J. Vervaet and S. F. Adali (eds.), Eurasian empires in antiquity and the early Middle Ages: contacts and exchange between the Graeco-Roman world, Inner Asia and China, Cambridge University Press: Cambridge, 2017, 133-150

‘Slavery’, in W. Scheidel (ed.), The Cambridge companion to the Roman economy, Cambridge University Press: Cambridge, 2012, 89-113

‘The Roman slave supply’, in: K. Bradley and P. Cartledge (eds.), The Cambridge world history of slavery, 1: The ancient Mediterranean world, Cambridge University Press: Cambridge 2011, 287-310

‘The comparative economics of slavery in the Greco-Roman world’, in: E. Dal Lago and C. Katsari (eds.), Slave systems, ancient and modern, Cambridge University Press: Cambridge, 2008, 105-126

‘Real slave prices and the relative cost of slave labor in the Greco-Roman world’, in: Ancient Society 35 (2005), 1-17

‘Human mobility in Roman Italy, II: The slave population’, in: Journal of Roman Studies 95 (2005), 64-79

‘Helot numbers: a simplified model’, in: N. Luraghi and S. E. Alcock (eds.), Helots and their masters in Laconia and Messenia: histories, ideologies, structures, Harvard University Press: Cambridge MA and London, 2003, 240-247

‘The hireling and the slave: a transatlantic perspective’, in: P. Cartledge, E. E. Cohen and L. Foxhall (eds.), Money, labour and land: approaches to the economies of ancient Greece, Routledge: London and New York, 2001, 175-184

Bellancourt-Valdher and J.-N. Corvisier (eds.), La démographie historique antique, Artois Presses Université: Arras, 1999, 107-115

‘The slave population of Roman Italy: speculation and constraints’, in: Topoi 9, 1 (1999), 129-144

‘Foreword’, in: M. I. Finley (ed.), Classical slavery, Frank Cass: London and Portland, Reprint 1999, VII-XIII

‘Moses I. Finley’, ‘Galley slaves’, ‘Ancient Mediterranean slave trade’, in: P. Finkelman and J. C. Miller (eds.), Macmillan encyclopedia of world slavery, vols. 1-2, Simon & Schuster Macmillan: New York, 1998, 332-333, 355-356, 830-831

‘Quantifying the sources of slaves in the early Roman empire’, in: Journal of Roman Studies 87 (1997), 156-169

Servus vicarius’, ‘Stoicism’, ‘Vernae’, in: J. P. Rodriguez (ed.), The Historical encyclopedia of world slavery, vol. 2, ABC-CLIO Press: Santa Barbara, 1997, 578-579, 611-612, 670-671

‘Reflections on the differential valuation of slaves in Diocletian’s price edict and in the United States’, in: Münstersche Beiträge zur antiken Handelsgeschichte 15, 1 (1996), 67-79

‘Frauen als Ware: Sklavinnen in der Wirtschaft der griechisch-römischen Welt’, in: E. Specht (ed.), Frauenreichtum: Die Frau als Wirtschaftsfaktor im Altertum, Wiener Frauenverlag: Vienna, 1994, 143-180

‘Columellas privates ius liberorum: Literatur, Recht, Demographie. Einige Probleme’, in: Latomus 53 (1994), 513-527

‘Sklaven und Freigelassene als Pächter und ihre ökonomische Funktion in der römischen Landwirtschaft (Colonus-Studien III)’, in: H. Sancisi-Weerdenburg et al. (eds.), De Agricultura: In memoriam Pieter Willem de Neeve (1945-1990), J. C. Gieben: Amsterdam, 1993, 182-196

Servi alieni als Erben: Zum gesellschaftlichen Hintergrund’, in: Zeitschrift der Savigny-Stiftung für Rechtsgeschichte, romanistische Abteilung 110 (1993), 648-651

‘Slavery and the shackled mind: on fortune-telling and slave mentality in the Graeco-Roman world’ [review essay on: F. Kudlien, Sklaven-Mentalität im Spiegel antiker Wahrsagerei, Stuttgart 1991], in: Ancient History Bulletin 7 (1993), 107-114

‘Free-born and manumitted bailiffs in the Graeco-Roman world’, in: Classical Quarterly 40 (1990), 591-593