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The concept of an H-cordial graph is introduced by 1. Cahit in
1996 (Bulletin of the ICA). But that paper has some lacunae and
invalid statements. We try to prove the statements whose proofs in
Cahit's paper are incomplete, and also we provide some
counterexamples. We also prove necessary and sufficient conditions
for H-cordiality of complete graphs and wheels and
$H_2$-cordiality of wheels.
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