@inbook{58e7cf7b1b4142fc9ebffbaadfa0ebcf,
title = "The O(4)D+! nonlinear sigma model:: The vacuum state and the mass gap",
abstract = "We study the ground state and low-lying excited states in the nonlinear sigma model with the coupled cluster method of quantum many-body theory.",
author = "NE Ligterink and NR Walet and RF Bishop",
year = "2000",
language = "English",
isbn = "981-02-4236-0",
series = "Proceedings from the Institute for Nuclear Theory",
publisher = "World Scientific Publishing Co. Pte. Ltd",
pages = "227--230",
editor = "N Isgur",
booktitle = "Quark Confinement and the Hadron Spectrum III",
address = "Singapore",
}