Working Google Scholar link: https://scholar.google.com/scholar?hl=en&as_sdt=7%2C39&q=trace+%22string+diagrams%22+%22Einstein+summation%22&btnG=#d=gs_qabs&t=17

Working Google Scholar link: https://scholar.google.com/scholar?hl=en&as_sdt=7%2C39&q=trace+%22string+diagrams%22+%22Einstein+summation%22&btnG=#d=gs_qabs&t=1714249856116&u=%23p%3Dbw0D4te4FGEJ https://scholar.google.com/scholar?hl=en&as_sdt=7%2C39&q=tra... Direct arXiv PDF link to first result: https://arxiv.org/pdf/1308.3586 https://arxiv.org/pdf/1308.3586