Citation:
{Puccetti} S, {Fiore} F, {D'Elia} V, {Pillitteri} I, {Feruglio} C, {Grazian} A, {Brusa} M, {Ciliegi} P, {Comastri} A, {Gruppioni} C. {The XMM-Newton survey of the ELAIS-S1 field. I. Number counts, angular correlation function and X-ray spectral properties}. \aap. 2006;457:501-515.
