ORCHIDS -- KLOPFENSTEIN, E. & Ph. TOUSSAINT. Orchidaceae Belgicae. 1987. 5 text- and 5 plate-vols. 8°-obl. and fol. Owrps. -- J. v. BODEGOM. Enige orchideeën van West Nieuw Guinea. 1973. Owrps. (Thesis). -- P. VERMEULEN. Studies on Dactylorchids. 1947. Owrps, (Thesis). -- M. BOURNÉRIAS, dir. Les orchidées de France, Belgique et Luxembourg. (1996). Or. limp brds. -- H.R. REINHARD, (u.a.). Die Orchideen der Schweiz und angrenzende Gebiete. (1991). Obrds. w. dust-j. -- M.C.M. WERKHOVEN. Orchideeën van Suriname/Orchids of Suriname. 1986. 4°. Obrds. w. dust-j. -- And 4 o. on orchids in 5 vols. (20).