2 literature references for Polymastia mammeata (Bowerbank, 1866):

Author: Bowerbank, J.S.
Year: 1866
Title: A Monograph of the British Spongiadae. Volume 2. (
Source: Ray Society: London): i-xx, 1-388.
Author: Arndt, W.
Year: 1935
Title: Porifera.
Source: In: Die Tierwelt der Nord- und Ostsee. 3a (27).(Leipzig): 1-140.