References

1

Andreani P., La Franca F., Christiani S. 1993, MNRAS 261, L35

2

Chini R., Krügel E., 1994, A&A, 288, L33

3

Isaak K.G., McMahon R.G., Hills R.E., Withington S. 1994, MNRAS 269, L28

4

McMahon R.G., Omont A., Bergeron J., Kreysa E., Haslam C.G.T. 1994, MNRAS 267, L9