Some comments on the paper: "Oxygen reduction mechanism of NdBaCo2O5+delta cathode for intermediate-temperature solid oxide fuel cells under cathodic polarization" by Haitao Gu, Han Chen, Ling Gao, Yifeng Zheng, Xiaofang Zhu and Lucun Guo, Int. J. Hydrogen Energy Volume 34, Issue 5 (2009) Pages 2416-2420