S., Turaev F., and Ilyasov A. S. “STRUCTURAL AND FUNCTIONAL ELEMENTS OF SPHINCTERS OF THE GASTROINTESTINAL TRACT OF HUMAN AND ANIMALS”. EUROPEAN JOURNAL OF MODERN MEDICINE AND PRACTICE, vol. 2, no. 2, Feb. 2022, pp. 54-61, http://inovatus.es/index.php/ejmmp/article/view/406.