Effect of Buffer Capacity when Mixing Phosphate and Carbonate buffer solution in different ratio together

I need a literature and hypothesis on what will happen when I have a mixed-buffer system. I will be mixing carbonate and phosphate buffer system in the following ratio (1:0, 4:1, 3:2, 2:3, 1:4, 0:1) under conditions of human blood at pH 7.40, 37.00 as well as Osmolarity of 0.283M. I want need to have a write-up and hypothesis (Supported by reason) on which ratio would be the best for buffering. Attached a relevant paper for you to help you. Please read up on more papers too