Key points are not available for this paper at this time.
Marnik G. Dekimpe, Dominique M. Hanssens, Sustained Spending and Persistent Response: A New Look at Long-Term Marketing Profitability, Journal of Marketing Research, Vol. 36, No. 4 (Nov., 1999), pp. 397-412
Dekimpe et al. (Mon,) studied this question.