Market efficiency and the long-memory of supply and demand: Is price impact variable and permanent or fixed and temporary?

Farmer, J. D., Gerig, A., Lillo, F., & Mike, S. (2006). Market efficiency and the long-memory of supply and demand: Is price impact variable and permanent or fixed and temporary? Quantitative Finance, 6(2), 107–112. https://doi.org/10.1080/14697680600668048