Yu. A. Bychkov, 1966, Zh. Eksperim. Teor. Fiz., 50, 738
I. E. Dzyaloshinsky, 1971, Zh. Eksperim. Teor. Fiz., 61, 791
E. H. Lieb, 1968, Phys. Rev. Lett., 20, 1445, 10.1103/PhysRevLett.20.1445
N. Menyhárd, 1973, J. Low Temp. Phys., 12, 529, 10.1007/BF00654955
J. Sólyom, 1973, J. Low Temp. Phys., 12, 546, 10.1007/BF00654956
S. Tomonaga, 1950, Prog. Theor. Phys., 5, 349, 10.1143/ptp/5.4.544
D. C. Mattis, 1965, J. Math. Phys., 6, 304, 10.1063/1.1704281
S. Engelsberg, 1964, Phys. Rev., 136, A1583, 10.1103/PhysRev.136.A1582
A. Luther, 1974, Phys. Rev. B, 9, 2911, 10.1103/PhysRevB.9.2911
A. Luther, 1974, Phys. Rev. Lett., 32, 992, 10.1103/PhysRevLett.32.992
D. C. Mattis, 1974, Phys. Rev. Lett., 32, 714, 10.1103/PhysRevLett.32.714
H. Fukuyama, 1974, Phys. Rev. Lett., 33, 305, 10.1103/PhysRevLett.33.305
W. Götze, 1972, Phys. Rev. B, 6, 1226, 10.1103/PhysRevB.6.1226
