Beitalmal , A.O. 2023. Absolutely Continuous Invariant Measures for Piecewise Expanding Chaotic Transformations in R^n with Summable Oscillations of Derivative. Journal of Pure & Applied Sciences . 22, 2 (Dec. 2023), 73–82. DOI:https://doi.org/10.51984/jopas.v22i2.2342.