Arsenic K-edge XANES study of REFeAsO oxypnictides W. Xu, B. Joseph, A. Iadecola, A. Marcelli, W. S. Chu, D. Di Gioacchino, A. Bianconi, Z. Y. Wu and N. L. Saini EPL, 90 5 (2010) 57001 Published online: 29 June 2010 DOI: 10.1209/0295-5075/90/57001