1. Tsukermann, A. M., and Terentiev, A. P., Proc. Intern. Conf. on Standards for a Common Language for Machine Searching and Translation, 1, 493 (Interscience Press, 1960).
2. Garfield, E., doctoral dissertation, Univ. of Pennsylvania (1961).
3. Harris, Z. S., Methods in Structural Linguistics (Univ. of Chicago Press, 1951).
4. Harris, Z. S., Annual Report of the Computing Centre (Univ. of Pennsylvania, Philadelphia, 1960).
5. Soffer, M. D., Science, 127, 880 (1958).