The authors did not cite references 64 and 65 anywhere in the main text. Meanwhile, reference [66] is used to refer to at least three completely different papers:
Schoenmaker et al. (2023); “UnCorrupt SMILES”
Bhadwal et al. (2023); “GenSMILES” (appears twice in the text)
Olivecrona et al. (2017); “Molecular de-novo design through deep reinforcement learning”
Furthermore, reference 69 is an exact duplicate of reference 66 (both are Bhadwal et al. 2023 “GenSMILES”).