1. Amnuel, P.R. & Guseinov, O.H. 1976, A&A 46, 163.
2. Batten, A.H., Fletcher, J.M. & MacCarthy, D.G. 1989, Publ. Dom. Ap. Obs. 17, 1.
3. Blaauw, A. 1961, Bull. Astron. Inst. Neth. 15, 265.
4. de Loore, C. & Sutantyo, W. 1984, ApSS 99, 335.
5. Garmany, C.D., Conti, P.S. & Marrey, P. 1980, ApJ 242, 1063.