P.WONGSRI, et al. “Preparation of Pooled Blood Samples to Use As a Proficiency Testing Material for Hemoglobin a1ctesting Byturbidimetric Inhibition Immunoassay”. International Journal of Pharma and Bio Sciences, vol. 9, no. 3, Sept. 2018, pp. 98-103, doi:10.22376/ijpbs.2018.9.3.b98-103.