Saeyup, Pipat. 2020. “Pediatric Endotracheal Tube Size Prediction: A Comparison among Ultrasound Measured Subglottic Diameter, Age-Formula and Little Fingernail Width Methods”. Thai Journal of Anesthesiology 46 (4):220-26. https://he02.tci-thaijo.org/index.php/anesthai/article/view/244895.