Book on Negation (Apophasis)

 https://archive.org/details/nagarjunaphilosophyofnagarjunavicentefatonemlbd_991_W/page/n7/mode/2up

Paul Deussen's translation of sixty upanisads

 https://archive.org/details/sixty-upanishads-of-the-veda-vol-2-paul-deussen/page/748/mode/2up

Beautiful India n philosophy book and great from the point of view of my research

 https://archive.org/details/indianphilosophycreativeperiodranade_202003_564_w/page/n7/mode/2up