Martinez Maestro, L, Haro-Gonzalez, P, del Rosal, B, Martin Rodriguez, E, Naccache, R, Cappobianco, JA, Dholakia, K, Garcia Sole, J, Jaque, D, "Optical trapping of NaYF4:Er3+,Yb3+ upconverting fluorescent nanoparticles", Nanoscale, 2013