The doctrine of Contract A and Contract B was established by:John Burrows Ltd$.$ v$.$ Subsurface Surveys Ltd$.$ et al$.,1968,$ Supreme Court of CanadaOwen Sound Public Library Board v$.$ Mial Developments Ltd$.$ et al$.,1979,$ Ontario Court of AppealsConwest Exploration Co$.$ Ltd$.$ et al$.$ v$.$ Letain, $1963,$ Supreme Court of Canada Ron Engineering et al$.$ v$.$ The Queen in right of Ontario et al$.,1981,$ Supreme Court of Canada