1. Theodorsson P: Measurements of Weak Radioactivity. World Scientific Pub. Co, Singapore; 1997.
2. TAEK: Resource of natural radiation. Accessed on: 11.03.2014., [ http://www.taek.gov.tr/bilgi-kosesi/184-radyasyon-insan-ve-cevre/radyasyonla-birlikte-yasiyoruz/501-dogal-radyasyon-kaynaklari.html ]
3. UNSCEAR: Report on sources and effects of ionizing radiation to the general assembly, United Nations, Vienna. 2000, Accessed on: 25.02.2014., [ http://www.unscear.org/unscear/en/publications/2000_1.html ]
4. Robertson GP: Geostatistics in ecology: interpolation with known variance. Ecology 1987, 68: 744–748. 10.2307/1938482
5. Cressie NAC: Statistics for Spatial Data. John Wiley and Sons, Inc, Canada; 1993.