Introduction to competitive bidding
Von der Porten, Ronald P.
Goren, Charles Henry,1901-1991.
Von der Porten, Ronald P.Introduction to defensive bidding.
London Hale
1985, c1984
Previous ed. published as: Introduction to defensive bidding / by Ronald P. Von der Porten. Englewood Cliffs : Prentice-Hall, 1967
Contract bridge