Nature-based interventions reduce physiological stress in children with chronic illnesses: evidence from salivary biomarkers. - Díaz-Martínez F; Sánchez-Sauco MF; Orenes-Piñero E; Hernández-Vera MJ; Robledano Aymerich F; Claudio L; Ortega-García JA (Frontiers in public health, 2025)