Designing spin-spin interactions with one and two dimensional ion crystals in planar micro trapsJ. Welzel, A. Bautista-Salvador, C. Abarbanel, V. Wineman-Fisher, C. Wunderlich, R. Folman and F. Schmidt-KalerEur. Phys. J. D, 65 1-2 (2011) 285-297DOI: https://doi.org/10.1140/epjd/e2011-20098-y