Sherwood, Dennis, and Jon Cooper. "Vector analysis and complex algebra." Crystals, X-rays and Proteins: Comprehensive Protein Crystallography. : Oxford University Press, 2010-11-04. Oxford Scholarship Online. 2011-01-01. Date Accessed 18 Jun. 2013 <http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199559046.001.0001/acprof-9780199559046-chapter-2>.
Sherwood, D., & Cooper, J.(2010-11-04). Vector analysis and complex algebra. In Crystals, X-rays and Proteins: Comprehensive Protein Crystallography. : Oxford University Press. Retrieved 18 Jun. 2013, from http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199559046.001.0001/acprof-9780199559046-chapter-2.
Sherwood, Dennis, and Jon Cooper. "Vector analysis and complex algebra." In Crystals, X-rays and Proteins: Comprehensive Protein Crystallography. : Oxford University Press, 2010-11-04. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199559046.001.0001/acprof-9780199559046-chapter-2.
Sherwood D, Cooper J. Vector analysis and complex algebra. In: Sherwood D, Cooper J. Crystals, X-rays and Proteins: Comprehensive Protein Crystallography. Oxford University Press; 2010. http://www.oxfordscholarship.com/view/10.1093/acprof:oso/9780199559046.001.0001/acprof-9780199559046-chapter-2. Accessed June 18, 2013.