Matos, G. D., Tarley, C. R. T., Ferreira, S. L. C. and Arruda, M. A. Z. (2005) “Use of experimental design in the optimisation of a solid phase preconcentration system for Cobalt determination by GFAAS”, Eclética Química, 30(1), pp. 65–74. doi: 10.26850/1678-4618eqj.v30.1.2005.p65-74.