D. Buono, G. Khan, K. B. von Hagen, P. A. Kosachev, E. Mayland-Quellhorst, S. L. Mosyakin, and D. C. Albach, "Comparative Phylogeography of Veronica spicata and V. longifolia (Plantaginaceae) Across Europe: Integrating Hybridization and Polyploidy in Phylogeography" Frontiers in Plant Science, vol. 11.
doi: 10.3389/fpls.2020.588354

S. Pfanzelt, J. Ptacek, P. Sklenar, K. B. von Hagen, and D. C. Albach, "Genome Size in South American Gentianella (Gentianaceae, Swertiinae), with a Special Emphasis on Species from the Bolivian and Ecuadorian Andes" Annals of the Missouri Botanical Garden, vol. 106.
doi: 10.3417/2020610

K. B. von Hagen, "Wilhelm Meyer (1867-1953) und der Botanische Garten zu Oldenburg - Naturkunde und Naturschutz als Lebensaufgabe" Oldenburger Forschungen, vol. 34.

S. Pfanzelt, D. C. Albach, and K. B. von Hagen, "Extremely low levels of chloroplast genome sequence variability in Astelia pumila (Asteliaceae, Asparagales)" PeerJ, vol. 7, p. 6244.
doi: 10.7717/peerj.6244

S. Pfanzelt, P. Sarhanova, D. C. Albach, and K. B. Hagen, "Tabula rasa in the Patagonian Channels II: The cushion peat bog species Astelia pumila (Asteliaceae) and Donatia fascicularis (Stylidiaceae) survived the last glacial in south-central Chile" Journal of Biogeography, vol. 46, iss. 5.
doi: 10.1111/jbi.13562

S. Pfanzelt, D. C. Albach, and K. B. von Hagen, "Tabula rasa in the Patagonian Channels? The phylogeography of Oreobolus obtusangulus (Cyperaceae)" Molecular Ecology, vol. 26, iss. 15.
doi: 10.1111/mec.14156

U. Aderholz, D. Albach, K. B. von Hagen, C. Hößle, U. Kapteina, and B. Weusmann, "Pflanzen forschend entdecken - Experimente zur Sekundarstufe 1." Baltmannsweiler: Schneider Verlag Hohengehren.

K. B. von Hagen, "Halenia." R. Benal S.R. Gradstein, C. M. Ed., Universidad Nacional de Colombia - Sede Bogotá., Facultad de Ciencias, Instituto de Ciencias Naturales: Universidad Nacional de Colombia - Sede Bogotá., Facultad de Ciencias, Instituto de Ciencias Naturales, vol. 1.

S. Pfanzelt and K. B. von Hagen, "Morphological variation of Gentiana section Chondrophyllae in South America and taxonomic implications" Plant Systematics and Evolution, vol. 302, iss. 2.
doi: 10.1007/s00606-015-1250-x

K. B. von Hagen, "Arzneipflanzengarten in Oldenburg" Die PTA in der Apotheke Heft, vol. 6, p. 115.

K. B. von Hagen, "Gentianaceae Juss. – Enziangewächse" , Rottensteiner, W. K. Ed., Klagenfurt: Naturwissenschaftlicher Verein für Kärnten, Klagenfurt.

J. W. Kadereit and K. B. von Hagen, "Vom Werden der Vielfalt: Artbildung am Beispiel der Enziangewächse" , Beck, E. Ed., Weinheim: Wiley VCH.

H. R. Hamasha, K. B. von Hagen, and M. Röser, "Stipa (Poaceae) and allies in the Old World: molecular phylogenetics realigns genus circumscription and gives evidence on the origin of American and Australian lineages" Plant Systematics and Evolution, vol. 298, iss. 2.
doi: 10.1007/s00606-011-0549-5

M. H. Hoffmann, K. B. von Hagen, E. Hörandl, M. Röser, and N. V. Tkach, "Sources of the Arctic Flora: Origins of Arctic Species in Ranunculus and Related Genera" International Journal of Plant Sciences, vol. 171, iss. 1.
doi: 10.1086/647918

U. Wahrmund, H. Heklau, M. Röser, A. Kästner, E. Vitek, F. Ehrendorfer, and K. B. von Hagen, "A molecular phylogeny reveals frequent changes of growth form in Carlina (Asteraceae)" Taxon, vol. 59, iss. 2.
doi: 10.1002/tax.592003

P. Maas, L. Struwe, and K. B. von Hagen, "Gentianaceae" , Hokche O., B. P. E. and Huber, O. Eds., Fundación Instituto Botánico de Venezuela Dr. Tobias Lasser, Caracas. vol. Nuevo Catálogo de la Flora Vascular de Venezuela.

P. Chassot and K. B. von Hagen, "Pollen morphology of the Swertiinae (Gentianaceae): phylogenetic implications" Botanical Journal of the Linnean Society, vol. 157, iss. 2.
doi: 10.1111/j.1095-8339.2008.00798.x

B. K. von Hagen, G. Seidler, and E. Welk, "New evidence for a postglacial homoploid hybrid origin of the widespread Central European Scabiosa columbaria L. s. str. (Dipsacaceae)" Plant Systematics and Evolution, vol. 274, iss. 3-4.
doi: 10.1007/s00606-008-0046-7

N. V. Tkach, M. H. Hoffmann, M. Röser, and K. B. von Hagen, "Temporal patterns of evolution in the Arctic explored in Artemisia L. (Asteraceae) lineages of different age" Plant Ecology & Diversity, vol. 1, iss. 2.
doi: 10.1080/17550870802331912

K. B. von Hagen, "Description of new taxa of Halenia Borkh. (Gentianaceae) from Colombia and Venezuela with significance for testing a key innovation hypothesis" Organisms Diversity and Evolution, vol. 7, iss. 1.
doi: 10.1016/j.ode.2005.11.003

N. V. Tkach, M. H. Hoffmann, M. Röser, A. A. Korobkov, and K. B. von Hagen, "Parallel evolutionary patterns in multiple lineages of arctic Artemisia L. (Asteraceae)" Evolution.
doi: 10.1111/j.1558-5646.2007.00270.x

T. Oppen and K. B. von Hagen, Botanische Flugobjekte - 5 Bastelbögen zum Experimentieren. Selbstverlag, verkaufte Auflage 400x.

K. B. von Hagen, "Revidierte Belege aus dem "Herbarium Istriacum"" , Starmühler, W. Ed.,

K. B. von Hagen, "Checklist für die Gentianaceae" , Starmühler, W. Ed.,

K. B. von Hagen, "SpecRat 1.0, a small computer program to study shifts in speciation rates" Schlechtendalia, vol. 10.

K. B. von Hagen and J. W. Kadereit, "The diversification of Halenia (Gentianaceae): Ecological opportunity versus key innovation" Evolution, vol. 57, iss. 11.
doi: 10.1111/j.0014-3820.2003.tb01495.x

K. B. von Hagen and J. W. Kadereit, "Phylogeny and Flower Evolution of the Swertiinae (Gentianaceae-Gentianeae): Homoplasy and the Principle of Variable Proportions" Systematic Botany, vol. 27, iss. 3.

L. Struwe, J. W. Kadereit, J. Klackenberg, J. Nilsson, M. Thiv, K. B. von Hagen, and V. Albert, "Systematics, character evolution, and biogeography of Gentianaceae, including a new tribal and subtribal classification" , Struwe, L. and Albert, V. A. Eds., Cambridge: Cambridge University Press.

K. B. von Hagen and J. W. Kadereit, "The phylogeny of (Gentianaceae) and its colonization of the southern hemisphere as revealed by nuclear and chloroplast DNA sequence variation" Organisms Diversity and Evolution, vol. 1, iss. 1.
doi: 10.1078/1439-6092-00005

K. B. von Hagen and J. W. Kadereit, "Notes on the systematics and evolution of Gentiana sect. Ciminalis" Bot. Jahrb. Syst, vol. 122.

K. B. Hungerer and J. W. Kadereit, "The phylogeny and biogeography of Gentiana L. sect. Ciminalis (Adans.) Dumort.: A historical interpretation of distribution ranges in the European high mountains" Perspectives in Plant Ecology, Evolution and Systematics, vol. 1, iss. 1.
doi: 10.1078/1433-8319-00055