Retnaningtyas, Lucia, Subijanto Sudarmo, Ariyanto Harsono, and Sylviati Damanik. 2008. “Effect of Probiotic on the Fecal SlgA Level in Preterm Infants (A Randomized Double-Blind Placebo Control Study)”. Paediatrica Indonesiana 48 (4), 246-52. https://doi.org/10.14238/pi48.4.2008.246-52.