Astuti, G., G. Cristofolini, L. Peruzzi, and P. Pupillo. “A New Subspecies of Pulmonaria officinalis (Boraginaceae) from the Southern Alps”. Phytotaxa, vol. 186, no. 3, Nov. 2014, pp. 148–157, doi:10.11646/phytotaxa.186.3.3.