http://slugsite.us/bow/pan/pickens.html
http://slugsite.us/bow/nudwk292.htm
http://slugsite.us/bow/clark_3.htm
http://slugsite.us/bow/hans_pic.htm
http://www.inbio.ac.cr/papers/babosasmarinas/ingles/listadeesp.htm
http://www.medslugs.de/E/Pac-E/Tritonicula_pickensi/Selection.htm
http://scottpenny.smugmug.com/gallery/3881249_R9eMK/7