Portela-Gornes Guida Maria, Grimelius Lars, Petersson Roland, and Bergström Reinhold. 1984. “Enterochromaffin Cells in the Rat Gastrointestinal Tract: Aspects of Factors Influencing Quantification”. Upsala Journal of Medical Sciences 89 (3):189-203. https://doi.org/10.3109/03009738409179499.