1. Chiu, W. K. and Cheung, K. C. (1977) An Economic Study of X̄-Charts with Warning Limits. J. Qual. Tech., 9, 166–171.
2. Collani, E. v. (1986) Shewhart-Karten mit und ohne Warngrenzen. Statistische Hefte, 27, 255–277.
3. Collani, E.v. (1989) The Economic Design of Control Charts.B. G. Teubner, Stuttgart.
4. Duncan, A. J. (1956) The Economic Design of X̄-Charts Used to Maintain Current Control of a Process. J. Amer. Statist. Ass., 51, 228–242.
5. Gordon, G. R. and Weindling, J. I. (1975) A Cost Model for Economic Design of Warning Limit Control Chart Schemes. AIIE Transactions, 7, 319–329.