What was known about the Martian magnetosphere before Phobos-2 mission

The only source of experimental data on martian magnetosphere before 1989 was the results of plasma and magnetic field measurements from Mars orbiters Mars 2, 3 and 5. The features of martian magnetosphere similar to proper features of magnetospheres of Earth and Venus were revealed; some evidences in favour of the existence of martian intrinsic magnetic field are mentioned.