Is it obligatory to pause reading to recite the Basmala before reciting a Quranic verse mentioned within the textual context of a book, or should the verse be read as connected to the text?

It is prescribed to recite the Basmala at the beginning of any surah in the Quran except Surah Bara'ah. It is also permissible to recite it when starting from the middle of a surah. However, as for reciting the Basmala when quoting verses included in books of Tafsir (exegesis) or other works, there is no evidence to support its permissibility. Furthermore, what is part of the Quran within books of Tafsir or other works does not take the ruling of a Mus'haf (a physical copy of the Quran).