Sheen, Patricia; Oberhelman, Richard A.; Gilman, Robert H.; Cabrera, Lilly; Verastegui, Manuela; Madico, Guillermo (1 May 1995). "Short Report: A Placebo-Controlled Study of Lactobacillus GG Colonization in One-to-Three-Year-Old Peruvian Children". The American Journal of Tropical Medicine and Hygiene. 52 (5): 389–392. doi:10.4269/ajtmh.1995.52.389. PMID7771602.
Sheen, Patricia; Oberhelman, Richard A.; Gilman, Robert H.; Cabrera, Lilly; Verastegui, Manuela; Madico, Guillermo (1 May 1995). "Short Report: A Placebo-Controlled Study of Lactobacillus GG Colonization in One-to-Three-Year-Old Peruvian Children". The American Journal of Tropical Medicine and Hygiene. 52 (5): 389–392. doi:10.4269/ajtmh.1995.52.389. PMID7771602.