Khalifa, H., Ahmed, A.A., Abusaediyah, A., Yousuf, A. and Grimida, S. 2017. GAS CHROMATOGRAPHY - MASS SPECTROMETRY (GC-MS) IN ORGANIC GEOCHEMICAL INVESTIGATION OF CRUDE OILS FROM KIKINDA AND VELEBIT FIELDS IN SERBIA. International Journal of Research -GRANTHAALAYAH. 5, 6 (Jun. 2017), 550–560. DOI:https://doi.org/10.29121/granthaalayah.v5.i6.2017.2073.