Metformin Potentiates the Antidiabetic Properties of Annona muricata and Tapinanthus globiferus Leaf Extracts in Diabetic Rats, Atanu, Francis O., Avwioroko Oghenetega J., Ilesanmi Omotayo B., and Yakubu Ojochenemi E. , Pharmacognosy Journal, May 2021, Volume 13, Issue 3, p.614-619, (2021)