Premonoidal Categories and a Graphical View of Programs (Jeffrey, 1997)

@article{jeffrey1997:premonoidal,
  title={Premonoidal categories and a graphical view of programs},
  author={Jeffrey, Alan},
  journal={Preprint at ResearchGate},
  url={https://www.researchgate.net/profile/Alan-Jeffrey/publication/228639836_Premonoidal_categories_and_a_graphical_view_of_programs/links/00b495182cd648a874000000/Premonoidal-categories-and-a-graphical-view-of-programs.pdf},
  year={1997}
}