N,N- and N,O-6-membered Ring peri-Annelation in Naphthalene. Is it a Heteroring or merely a peri- Heterobridge?

Citation:

Tzeli D, Tsoungas PG. N,N- and N,O-6-membered Ring peri-Annelation in Naphthalene. Is it a Heteroring or merely a peri- Heterobridge?. CHEMISTRYSELECT 2021;6:951-961.