Spectral Properties of Underdoped Cuprates

Theory of Spin Excitations in Undoped and Underdoped Cuprates

The Spin Gap and Superconducting States of Underdoped Cuprates

Orbital currents and cheap vortices in underdoped cuprates

Charge dynamics in electron-underdoped high-Tc cuprates

Real-Space Holon Pairing in Underdoped Cuprates

t-J Model and the Gauge Theory Description of Underdoped Cuprates