E. Busemann-Sokole, “Measurement of Collimator Hole Angulation and Camera Head Tilt for Slant and Parallel Hole Collimators Used in SPECT,” Journal of Nuclear Medicine, Vol. 28, No. 10, 1986, pp. 1592-1598.
 M. Eckholt and H. Bergmann, “Angulation Errors in Parallel-Hole and Fan Beam Collimators: Computer Controlled Quality Control and Acceptance Testing Procedure,” Journal of Nuclear Medicine, Vol. 41, No. 3, 2000 pp. 548-555.
 Y. Takahashi, K. Murase, H. Higashno, et al., “SPECT Imaging with Off-Set Detector System: Comparison of Sampling Angles 2, 4 and 6 Degrees,” Annals of Nuclear Medicine, Vol. 16, No. 5, 2002, pp. 343-347. doi:10.1007/BF02988623
 H. Hines, R. Kayayan, J. Colsher, et al., “Recommendations for Implementing SPECT Instrumentation Quality Control. Nuclear Medicine Section—National Electrical Manufacturers Association,” European Journal of Nuclear Medicine and Molecular Imaging, Vol. 26, No. 5, 1999, pp. 527-532. doi:10.1007/s002590050421
 Web Site of National Instruments Corporation. www.NI.com.
 H. Z. Zeinali and A. Mirzai, “Design an Adaptive Quality Control Phantom to optimize Integral and Differential Uniformity, Collimator Hole angulation and Center of Rotation of SPECT,” The Journal of Instrumentation, Vol. 3, 2008, pp. 1-8. doi:10.2174/157340508784356743
 H. Z. Zeinali, M. Ghiassi-Nejad and A. Mirzai, “Design an Adaptive Quality Control Phantom to Optimize Uniformity, Collimator Hole Angulation and Center of Rotation of SPECT,” The Journal of Instrumentation, 2008.www.iop.org/EJ/jinst