TITLE
"On the Roles of Exposure Number in the Classical Credibility Theory,"Journal of Insurance Issues, Li-Hua Lai. January 1991, Vol. XIV, No. 1, pp. 39-43.

ABSTRACT
Using the perturbation in the 1/N,M as the exposure number, the leading correction to the claim number in the Longley-Cook theory is obtained. It is found that the correction term can not be neglected for common situations.