Costanzo, Emanuele, et al. « A phytosociological survey of the main plant community types of alpine and sub-alpine belt in the Sibillini Mountains (Central Apennines, Italy) ». Lazaroa, vol. 30, février 2010, p. 219-50, https://revistas.ucm.es/index.php/LAZA/article/view/LAZA0909110219A.