  The concept of an H-cordial graph is introduced by I. Cahit in 1996 (Bulletin
of the ICA). But that paper has some gaps and invalid statements. We try to
prove the statements whose proofs in Cahit's paper have problems, and also we
give counterexamples for the wrong statements. We prove necessary and
sufficient conditions for H-cordiality of complete graphs and wheels and
H_2-cordiality of wheels, which are wrongly claimed in Cahit's paper.
