Template:Gordon et al., 2009a
- Gordon, D.P., Cooper, R.A. & Campbell, H.J. 2009. 22. Phylum Hemichordata: acorn worms, pterobranchs, graptolites. Pp. 401–408 in: Gordon, D.P. (ed.). 2009. New Zealand inventory of biodiversity. Volume 1. Kingdom Animalia. Radiata, Lophotrochozoa, Deuterostomia. Canterbury University Press: Christchurch, New Zealand. ISBN 978-1-87725772-8. Reference page.