William Nylander's Collected Lichenological Papers. Edited and prefaced by Teuvo Ahti. Volume I: Introduction and Lichenological Papers 1852-1862, Volume II: Lichenological Papers 1863-1868 with Addenda Nova ad Lichenographiam Europaeam 1865-1887; Volume II: Lichenological Papers 1869-1887; Volume IV: Lichenological Papers 1888-1900; Volume IV: Lichenological Papers 1888-1900; Volume V: Synopsis M