1997 IUCN red list of threatened plants (1997)

An environmental profile of the Black Sea Coast - Gillett, Harriet J. (WCMC, 1997)

Icones plantarum or figures, with brief descriptive characters and remarks, of new or rare plants, selected from the author's herbarium - Hooker, Joseph Dalton, 1817 -1911 (Longman, Rees, Orme, Brown, Green, & Longman, etc, 1932)

Journal of the Arnold Arboretum - Arnold Arboretum. (Arnold Arboretum, Harvard University [etc.], 1967)

Just's Botanischer Jahresbericht - Just, Johann Leopold, 1841 -1891 (Gebruder Borntraeger, 1925)