Flavor asymmetry $\bar u-\bar d$ in the nucleon
  We give a brief summary of the Gottfried sum rule and a flavor asymmetric distribution $\bar u-\bar d$ in the nucleon. First, experimental history of the sum-rule studies is discussed. Second, future prospects for studying the asymmetry at Fermilab and RHIC are discussed. We also comment on possible nuclear modification. 
S. Kumano (Saga University)