Haug, T., S. Ebling, P. Boyes Braem, K. Tissi, and S. Sidler-Miserez. “Sign Language Learning and Assessment in German Switzerland: Exploring the Potential of Vocabulary Size Tests for Swiss German Sign Language”. Language Education & Assessment, vol. 2, no. 1, Apr. 2019, pp. 20-40, doi:10.29140/lea.v2n1.85.