↑rner, Karl (1973). Stockhausen : life and work (yn Saesneg). Berkeley: University of California Press. t. 251. ISBN9780520032729.
↑Widdowson, Peter (1996). Thomas Hardy : Selected Poetry and Non-Fictional Prose (yn Saesneg). London: Macmillan Education, Limited. t. xx. ISBN9781349250820.