Source: https://www.cambridge.org/core/journals/development-and-psychopathology/article/codevelopment-of-externalizing-and-internalizing-symptoms-in-middle-to-late-childhood-sex-baseline-respiratory-sinus-arrhythmia-and-respiratory-sinus-arrhythmia-reactivity-as-predictors/7B40E2791691E45E7081F133B6EE0150