1. Apostel, L., Le problème formel des classifications empiriques, in La Classification dans les Sciences, Gembloux, Duculot, 1963, 157–230.
2. Poincaré, H., The logic of Infinity, Mathematics and Science: Last Essays, Dover Publications, 1912, 45–64.
3. Comte, A., Philosophie première: Cours de Philosophie positive, Leçons 1–45 (1830), Hermann, Paris, 1975, lesson 2. For more details, see lessons 36, 40 and 42.
4. Sapir, E., The Status of Linguistics as a Science, Language
5, No. 4 (1929), 207–214.
5. Whorf, B. L., Science and Linguistics, Technol. Rev., 42, No 6, (1940), 229–231, 247–248.