@article{RiaT13,
  author = {R. Riaza and C. Tischendorf},
  title = {Structural characterization of classical and memristive circuits
	with purely imaginary eigenvalues},
  journal = {Int. J. Circ. Theor. Appl.},
  year = {2013},
  volume = {41},
  pages = {273--294},
  doi = {10.1002/cta.798}
}