[1] INDIAN INST TECHNOL, NEW DELHI 110029, INDIA
[2] INDIAN INST TECHNOL, KANPUR 208016, UTTAR PRADESH, INDIA
[3] UNIV CALIF BERKELEY, BERKELEY, CA 94720 USA
[4] GEORGE WASHINGTON UNIV, WASHINGTON, DC 20052 USA
[5] UNIV SO CALIF, SCH BUSINESS ADM, LOS ANGELES, CA 90089 USA