\def \hyperj@nk {{}{page}{1}} \def \hypernoname {{}{footnote}{1}} \def \hyperj@nk {{}{page}{2}} \def \hypernoname {{}{enumi}{1.}} \def \hypernoname {{}{enumi}{2.}} \def \hypernoname {{}{enumi}{3.}} \def \hypernoname {{}{enumi}{4.}} \def \hypernoname {{}{enumi}{1.@}} \def \hypernoname {{}{enumi}{2.@}} \def \hyperj@nk {{}{page}{3}} \def \hypernoname {{}{table}{1}} \def \hypernoname {{}{table}{2}} \def \hypernoname {{}{table}{2@}} \def \hyperj@nk {{}{page}{4}} \def \hyperj@nk {{}{page}{5}} \def \hypernoname {{}{reference}{reference.Chapman 1986}} \def \hypernoname {{}{reference}{reference.Ehrenberg 1981}} \def \hypernoname {{}{reference}{reference.Ehrenberg 1978}} \def \hypernoname {{}{reference}{reference.CSO 1988}} \def \hypernoname {{}{reference}{reference.Kopka \& Daly 1993}} \def \hypernoname {{}{reference}{reference.Kroonenberg 1994}} \def \hypernoname {{}{reference}{reference.Lamport 1986}} \def \hypernoname {{}{reference}{reference.MSC 1979/80}} \def \hypernoname {{}{reference}{reference.Reese forthcoming}} \def \hypernoname {{}{reference}{reference.Reynolds 1983}} \def \hypernoname {{}{reference}{reference.Thibault et al. 1993}} \def \hypernoname {{}{reference}{reference.Townsend 1970}} \def \hypernoname {{}{reference}{reference.Tufte 1983}} \def \hyperj@nk {{}{page}{6}} \def \hypernoname {{}{footnote}{2}} \def \hyperj@nk {{}{page}{7}} \def \hypernoname {{}{footnote}{3}} \def \hypernoname {{}{enumi}{1.@@}} \def \hypernoname {{}{footnote}{4}} \def \hypernoname {{}{enumi}{2.@@}} \def \hypernoname {{}{footnote}{5}} \def \hypernoname {{}{footnote}{6}} \def \hypernoname {{}{enumi}{1.@@@}} \def \hypernoname {{}{enumi}{2.@@@}} \def \hypernoname {{}{enumi}{3.@}} \def \hyperj@nk {{}{page}{8}} \def \hypernoname {{}{enumi}{4.@}} \def \hypernoname {{}{enumi}{5.}} \def \hypernoname {{}{enumi}{6.}} \def \hyperj@nk {{}{page}{9}} \def \hypernoname {{}{equation}{1}} \def \hypernoname {{}{equation}{2}} \def \hypernoname {{}{equation}{3}} \def \hypernoname {{}{equation}{4}} \def \hypernoname {{}{equation}{5}} \def \hypernoname {{}{equation}{6}} \def \hyperj@nk {{}{page}{10}} \def \hypernoname {{}{equation}{7}} \def \hypernoname {{}{footnote}{7}} \def \hypernoname {{}{equation}{8}} \def \hypernoname {{}{equation}{9}} \def \hypernoname {{}{equation}{10}} \def \hypernoname {{}{equation}{11}} \def \hyperj@nk {{}{page}{11}} \def \hyperj@nk {{}{page}{12}} \def \hyperj@nk {{}{page}{13}} \def \hyperj@nk {{}{page}{14}} \def \hyperj@nk {{}{page}{15}} \def \hyperj@nk {{}{page}{16}} \def \hyperj@nk {{}{page}{17}} \def \hypernoname {{}{enumi}{1.@@@@}} \def \hypernoname {{}{enumi}{2.@@@@}} \def \hypernoname {{}{enumi}{3.@@}} \def \hypernoname {{}{enumi}{4.@@}} \def \hyperj@nk {{}{page}{18}} \def \hypernoname {{}{footnote}{8}} \def \hyperj@nk {{}{page}{19}} \def \hyperj@nk {{}{page}{20}} \def \hyperj@nk {{}{page}{21}} \def \hyperj@nk {{}{page}{22}} \def \hypernoname {{}{preqn}{11}} \def \hypernoname {{}{preqn}{12}} \def \hypernoname {{}{preqn}{13}} \def \hypernoname {{}{preqn}{14}} \def \hypernoname {{}{preqn}{15}} \def \hypernoname {{}{preqn}{16}} \def \hypernoname {{}{preqn}{17}} \def \hypernoname {{}{preqn}{18}} \def \hypernoname {{}{preqn}{19}} \def \hypernoname {{}{preqn}{20}} \def \hypernoname {{}{preqn}{21}} \def \hypernoname {{}{preqn}{22}} \def \hyperj@nk {{}{page}{23}} \def \hyperj@nk {{}{page}{24}} \def \hyperj@nk {{}{page}{25}} \def \hyperj@nk {{}{page}{26}}