- RePEc:cem:doctra:322
- RePEc:cla:levrem:321307000000000211
- RePEc:col:001038:002534
- RePEc:col:001029:002520
- RePEc:col:001051:002527
- RePEc:col:001051:002528
- RePEc:col:001051:002529
- RePEc:fri:fribow:393
- RePEc:han:dpaper:dp-343
- RePEc:hhs:osloec:2006_014
- RePEc:anc:wpspec:3
- RePEc:auu:dpaper:528
- RePEc:irv:wpaper:050616