TY - JOUR AU - Jon Hougen AU - W Meerts AU - I Ozier C2 - Journal of Molecular Spectroscopy DA - 1991-01-01 LA - en M1 - 146 PB - Journal of Molecular Spectroscopy PY - 1991 TI - The Use of Extended Permutation-Inversion Groups in Constructing Hyperfine Hamiltonians for Symmetric-Top Internal Rotor Molecules like H3C-SiH3 ER -