- KOBA, K., et al. Antibacterial Activities of the Buds Essential Oil of Syzygium Aromaticum (L.) Merr. & Perry from Togo. Journal of Biologically Active Products from Nature, 2011, vol. 1, no. 1. pp. 42-51.
- How Drinking Grapefruit Juice Could Increase Your Cervical Mucus by Lindsay Meisel, 2017, online source: https://www.avawomen.com/avaworld/grapefruit-juice-cervical-mucus/
- How to Increase Your Fertility by Janet Stephens, book’s online source: https://books.google.pl/books?hl=en&lr=&id=hXrgDwAAQBAJ&oi=fnd&pg=PP11&dq=grapefruit+juice+fertility+cervical+mucus&ots=h-9d6b_M9k&sig=TjAHHTFK7GS9lKCLxW-OKhDQnbA&redir_esc=y#v=onepage&q=grapefruit%20juice%20fertility%20cervical%20mucus&f=false
- Portuguese Proverbs and Quotes for Every Day, https://www.superprof.com/blog/portuguese-sayings/
- 5 Important Portuguese Proverbs You Should Know, https://www.languageoasis.com/blog/5-important-portuguese-proverbs-you-should-know/