Lyubomirova, V., Belovezhdova, I., Kamusheva, A., Ignatov, P. and Tuhchiev, P. 2026. Optimization of Solid-phase Extraction and GC-MS/MS Determination of PAHs in Bulgarian Sewage Sludge. Proceedings of the Bulgarian Academy of Sciences. 79, 3 (Mar. 2026), 312–320. DOI:https://doi.org/10.7546/CRABS.2026.03.04.