More Than Two, Franklin Veaux & Eve Rickert-2014

https://www.amazon.com/More-Than-Two-Practical-Polyamory/dp/0991399706/ref=pd_lpo_3?pd_rd_i=0991399706&psc=1

The Ethical Slut, Third Edition: A Practical Guide to Polyamory, Open Relationships, and Other Freedoms in Sex and Love, Dossie Easton & Janet Hardy–2017

https://www.amazon.com/Ethical-Slut-Third-Practical-Relationships/dp/0399579664/ref=sr_1_1?crid=VA2HLYOG3PP7&keywords=the+ethical+slutt+third+edition&qid=1638071288&s=books&sprefix=The+Ethical+%2Cstripbooks%2C252&sr=1-1