References
- Andronov , A. A. , Leontovich , E. A. , Gordon , I.I. and Maier , A. G. 1973 . Qualitative Theory of Second‐Order Dynamic Systems , New York : John Wiley and Sons .
- Bourhis , R. Y. 1982 . “ Language policies and language attitudes: le monde de la francophonie ” . In In Attitudes Towards Language Variation: Social and Applied Contexts , Edited by: Ryan , E. D. and Giles , R. 34 – 66 . London : Edward Arnold .
- Bourhis , R. Y. 1984 . Conflict and Language Planning in Quebec , Clevedon : Multilingual Matters .
- Butler , G. J. , Freedman , H. I. and Waltman , P. 1986 . Uniformly persistent systems . Proc. Amer. Math. Soc. , 96 : 425 – 430 .
- Clark , C. W. 1976 . Mathematical Bioeconometrics: The Optimal Management of Renewable Resources , New York : Wiley‐Interscience .
- Coddington , E. A. and Levinson , N. 1955 . Theory of Ordinary Differential Equations , New York : McGraw‐Hill .
- Cooper , R. L. , ed. 1982 . Language Spread: Studies in Diffusion and Social Change , Bloomington : Indiana University Press .
- Fishman , J. A. , ed. 1978 . Advances in the Study of Societal Multilingualism , The Hague : Mouton .
- Freedman , H. I. 1980 . Deterministic Mathematical Models in Population Ecology . Edmonton, HIFR Consulting Ltd ,
- Freedman , H. I. and Gopalsamy , K. 1986 . Global stability in time‐delayed single species dynamics . Bull. Math. Biol. , 48 : 485 – 492 .
- Freedman , H. I. , Rai , B. and Waltman , P. 1986 . Mathematical models of population interactions with dispersal II: Differential survival in a change of habitat . J. Math. Anal. Appl. , 115 : 140 – 154 .
- Freedman , H. I. and Waltman , P. 1977 . Mathematical models of population interaction with dispersal I: Stability of two habitats with and without a predator . SIAM J. Appl. Math. , 32 : 631 – 648 .
- Freedman , H. I. and Waltman , P. 1978 . Predator influence on the growth of a population with three genotypes . J. Math. Biol. , 6 : 367 – 374 .
- Freedman , H. I. and Waltman , P. 1984 . Persistence in models of three interacting predator‐prey populations . Math. Biosci. , 68 : 213 – 231 .
- Freedman , H. I. and Waltman , P. 1985 . Persistence in a model of three competitive populations . Math. Biosci. , 73 : 89 – 101 .
- Keyfitz , N. 1977 . Introduction to the Mathematics of Population with Revisions , Reading : Addison‐Wesley .
- Lancaster , P. L. and Tismenetsky , M. 1985 . Tlie Vieory of Matrices, Second Edition , New York : Academic Press .
- LaSalle , J. and Lefschetz , S. 1961 . Stability by Liapunov's Direct Method , New York : Academic Press .
- Lewis , E. G. 1982 . “ Movements and agencies of language spread: Wales and the Soviet Union compared ” . In Language Spread: Studies in Diffusion and Social Change , Edited by: Cooper , R. L. 214 – 259 . Bloomington, Indiana University Press .
- Lieberson , S. 1982 . “ Forces affecting language spread: some basic propositions ” . In Language Spread: Studies in Diffusion and Social Change , Edited by: Cooper , R. L. 37 – 62 . Bloomington : Indiana University Press .
- McRae , K. D. 1983 . Conflict and Compromise in Multilingual Societies: Switzerland , Waterloo : Wilfred Laurier University Press .
- Sharma , P. G. and Kumar , S. 1977 . Indian Bilingualism , Agra : Kendriya Hindi Sansthaa .
- Vallee , F. G. and de Vries , J. 1978 . “ Trends in bilingualism in Canada ” . In Advances in the Study of Societal Multilingualism , Edited by: Fishman , J. A. 761 – 792 . The Hague : Mouton .
- Wagner , S. T. 1981 . “ The historical background of bilingualism and biculluralism in the United States ” . In The New Bilingualism. An American Dilemma , Edited by: Ridge , M. 29 – 52 . Los Angeles : University of Southern California Press .
- Wardhough , R. 1987 . Languages in Competition: Dominance, Diversity and Decline , New York : Basil Blackwell .
- Research partially supported by the Natural Sciences and Engineering Research Council of Canada, Grant No. NSERC A 4823.