Tomas, F., Romero, J. and Turon, X. (2005) “Experimental evidence that intra-specific competition in seagrass meadows reduces reproductive potential in the sea urchin Paracentrotus lividus (Lamarck)”, Scientia Marina, 69(4), pp. 475–484. doi: 10.3989/scimar.2005.69n4475.