1. https://www.poetryfoundation.org/poems/44266/mending-wall
2. Aristotle, Physics, transl, by R Waterfield, Oxford World Classics, Oxford University Press, UK, 2008.
3. R Descartes, Discourse on Method, transl, by I Maclean, Oxford World Classics, Oxford University Press, UK, 2008.
4. P Oppenheim and H Putnam, Unity of science as a working hypothesis, Minnesota Stud. Philos. Sci., Vol.2, No.2, pp.3–36, 1958.
5. C von Linn, Systema Naturae, transl, by M S J Engel-Ledeboer and H Engel, HES & De Graaf Publishers, Netherlands, 2003.