Comment on papers “Effect of Ag substitution on the transport property and magnetoresistance of LaMnO3” [J. Magn. Magn. Mater. 248 (2002) 26] and “Possible magnetic phase separation in Ru-doped La0.67Ca0.33O3” [J. Magn. Magn. Mater. 257 (2003) 195]☆