1. Akashi, T., et al. (2005). Applied Physics Letters, 87, 174101.
2. Allard, L. (2009). Proceedings of Microscopy and Microanalysis, 15, 130.
3. Allen, L., et al. (2003). Optical angular momentum. London: Taylor & Francis.
4. Allen, L. J. (2011). In Scanning Transmission Electron Microscopy. S. J. Pennycook & P. D. Nellist (Eds.). New York: Springer.
5. Baba, N., & Katayama, E. (2008). Ultramicroscopy, 108, 239.