Lê, Q. V., Nguyen, H. D. K., Hoang, D. T., Phan, L. H., Tran, T. T., & Chau, V. T. (2026). DETERMINATION OF RADIOACTIVITY BASED ON UNFOLDED GAMMA SPECTRA USING THE GRAVEL METHOD AND RESPONSE MATRIX FROM MCNP SIMULATION. Ho Chi Minh City University of Education Journal of Science, 23(3). https://doi.org/10.54607/hcmue.js.23.3.5099(2026)