by de la Peña, L, Cetto, A M, Valdés-Hernández, A
Published in Physica scripta (07.10.2015)

by Eldridge, P S, Leyland, W J H, Mar, J D, Lagoudakis, P G, Winkler, R, Karimov, O Z, Henini, M, Taylor, D, Phillips, R T, Harley, R T
Published in arXiv.org (30.07.2008)

by Vandegrift, Guy
Published in European journal of physics (01.09.2002)