1. Alexander R McN (1981) Factors of safety in the structure of animals. Sci Prog Oxford 67:109–130
2. Alexander R McN (1982) Optima for animals. Arnold, London, 112 pp
3. Alexander R McN (1985) The ideal and the feasible: physical constraints on evolution. Biol J Linnean Soc 26:345–358
4. Barel CDN (1985) A matter of space. Constructional morphology of cichlid fishes. Thesis, Univ Leiden
5. Barel CDN, Anker G Ch, Witte F, Hoogerhoud RJC, Goldschmidt PT (1989) Constructional constraints and its ecomorphological implications. Acta Morphol Neerl Scand 27:1–2, 83–110