[1] Ekonom Univ Bratislave, Narodohosp Fak, Katedra Financii, Bratislava 85235 1, Slovakia
[2] Univ Glasgow, Glasgow G12 8LT, Lanark, Scotland
[3] Univ Canterbury, Dept Econ, Christchurch 8140, New Zealand
[4] Inst Tecnol Autonomo Mexico, Mexico City 10700, DF, Mexico