Vladimirov, V., S. Bancheva, and D. Ivanova. “Contribution to the Knowledge of Pontechium maculatum(Boraginaceae), a Species of High Conservation Concern in the Bulgarian Flora”. Proceedings of the Bulgarian Academy of Sciences, vol. 76, no. 2, Feb. 2023, pp. 203-10, doi:10.7546/CRABS.2023.02.04.