Smith, KL; Holland, ND; Ruhl, HA (July 2005). "Enteropneust production of spiral fecal trails on the deep-sea floor observed with time-lapse photography". Deep Sea Research Part I: Oceanographic Research Papers. 52 (7): 1228–1240. Bibcode:2005DSRII..52.1228S. doi:10.1016/j.dsr.2005.02.004.
Smith, KL; Holland, ND; Ruhl, HA (July 2005). "Enteropneust production of spiral fecal trails on the deep-sea floor observed with time-lapse photography". Deep Sea Research Part I: Oceanographic Research Papers. 52 (7): 1228–1240. Bibcode:2005DSRII..52.1228S. doi:10.1016/j.dsr.2005.02.004.