1. Atwood, J., 1984: The relationships of the slipper orchids (subfamilyCypripedioideae). ? Selbyana7, 129?247.
2. Brieger, F. G., Maatsch, R., Senghas, R., 1971: UnterfamilieCypripedioideae. ? InSchlechter, R., (Ed.): Die Orchideen (revised edition), pp. 161?198. ? Berlin, Hamburg: Paul Parey.
3. Burns-Balogh, P., 1983: A theory on the evolution of the exine inOrchidaceae. ? Amer. J. Bot.70, 1304?1312.
4. ?, 1985: Evolutionary trends in the androecium of theOrchidaceae. ? Pl. Syst. Evol.149, 119?134.
5. -Funk, V. A., 1986: A phylogenetic analysis of theOrchidaceae. ? Smithsonian Contributions to Botany, no.61, 79 pp. ? Washington, D.C.