@article{article,
title = {Preliminary notes on early stages in the growth of colonies of Hydractinia echinata (Flem.)},
author = {Schijfsma, K.},
year = {1939},
journal = {Archives Neerlandaises de Zoologie},
volume = {4},
pages = {93-102},
howpublished = "\url{https://eurekamag.com/research/023/400/023400911.php}"
}