V. Mazurov, and E. Khukhro. (2014)cite arxiv:1401.0300Comment: A few new solutions and references have been added. Preparation of the next 19th issue is underway, new problems are welcome, as well as comments on previous editions.
D. Levin. Proceedings of MEST 2012: Electronic structure methods with applications to experimental chemistry, volume 68 of Advances in Quantum Chemistry, chapter 2, Academic Press, (2014)
D. Spikol, and J. Eliasson. The 6th IEEE International Conference on Wireless, Mobile, and Ubiquitous Technologies in Education, page 137--141. IEEE, (2010)