TY - BOOK AU - Griffin, Allan TI - Excitations in a bose-condensed liquid T2 - Cambridge studies in low temperature physics; 4 SN - 978-0-521-43271-9 PY - 1993/// CY - Cambridge PB - Cambridge University Press KW - Bose-Einstein KW - Condensation KW - Helium KW - Superfluidity ER -