Fokkema, K., ‘Frisian Studies’, in The Year's Work in Modern Language Studies, Volume 8: Survey Year 1937, The Year's Work in Modern Language Studies, 8 (MHRA, 1937), pp. 228–32, doi:10.2307/25833452
Fokkema, K., ‘Frisian Studies’, in The Year's Work in Modern Language Studies, Volume 8: Survey Year 1937, The Year's Work in Modern Language Studies, 8 (MHRA, 1937), pp. 228–32, doi:10.2307/25833452