Grosskopf S (1993). “Measuring Cost Efficiency in the Property-Liability Insurance Industry – the Measurement of Efficiency in Life-Insurance, Estimates of a Mixed Normal Gamma Error Model – X-Efficiency in the United-States Life-Insurance Industry – Comments.” J Banking and Finance 1: 511-513.
Grosskopf S (1993). “Measuring Cost Efficiency in the Property-Liability Insurance Industry – the Measurement of Efficiency in Life-Insurance, Estimates of a Mixed Normal Gamma Error Model – X-Efficiency in the United-States Life-Insurance Industry – Comments.” J Banking and Finance 1: 511-513.