Vein reticulation in seed ferns of the Dobrudzha coalfield Bulgaria - Tenchov, Yanaki Georgiev (Array, 2012)
International Geosciencies Program (IGCP) Project 575 (20120-2015) : "Pennsylvanian terrestrial habitats and biotas of southeastern Europe and northern Asia Minor and their relation to tectonics and climate", Zagreb, 6th and 7th of September 2011