1 ARP, H.C. 1958A, ASTRON. J. 63, 118. 2 ARP, H.C. 1958B, ASTRON. J. 63, 341. 3 BRAES, L.L.E. 1961, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 20, 7. 4 BRAES, L.L.E. 1962A, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 21, 16. 5 BRAES, L.L.E. 1962B, BULL. ASTRON. INST. NETH. 16, 297. 6 CORBEN, P.M. 1966, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 25, 44. 7 CORBEN, P.M. 1971A, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 30, 37. 8 CORBEN, P.M. 1971B, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 30, 79. 9 CORBEN, P.M. AND AL. 1968, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 27, 11. 10 COUSINS, A.W.J. 1961, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 20, 16. 11 COUSINS, A.W.J. AND AL. 1962, ROY. OBSERV. BULL. NO 49. 12 COUSINS, A.W.J. AND AL. 1963, ROY. OBSERV. BULL. NO 64. 13 COUSINS, A.W.J. AND AL. 1966, ROY. OBSERV. BULL. NO 121. 14 COUSINS, A.W.J. AND AL. 1970, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 29, 91. 15 EGGEN, O.J. 1963A, ASTRON. J. 68, 483. 16 EGGEN, O.J. 1963B, ASTRON. J. 68, 697. 17 EGGEN, O.J. 1964, ROY. OBSERV. BULL. NO 84. 18 EVANS, D.S. 1966, ROY. OBSERV. BULL. NO 110. 19 EVANS, D.S. AND AL. 1959, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 18, 144. 20 EVANS, D.S. AND AL. 1964, ROY. OBSERV. BULL. NO 85. 21 FEAST, M.W. AND AL. 1960, MONTHLY NOTICES ROY. ASTRON. SOC. 122, 239. 22 FERNIE, J.D. 1959, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 18, 57. 23 FERNIE, J.D. 1962, ASTROPHYS. J. 135, 298. 24 IRWIN, J.B. 1961, ASTROPHYS. J. SUPPL. VI, 253. 25 JANKOWITZ, N.E. AND AL. 1963, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 22, 18. 26 KOELBLOED, D. 1959, BULL. ASTRON. INST. NETH. 14, 265. 27 LAKE, R. 1962A, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 21, 56. 28 LAKE, R. 1962B, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 21, 191. 29 LAKE, R. 1963, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 22, 79. 30 LAKE, R. 1964A, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 23, 14. 31 LAKE, R. 1964B, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 23, 136. 32 LAKE, R. 1965, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 24, 41. 33 STOY, R.H. 1963, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 22, 157. 34 STOY, R.H. 1965, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 24, 29. 35 STOY, R.H. 1968, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 27, 119. 36 WILLIAMS, P.M. 1966, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 25, 122. 37 WILLIAMS, P.M. 1967, MONTHLY NOTES ASTRON. SOC. STH. AFRICA 26, 30. 38 COUSINS, A.W.J., PRIVATE COMMUNICATION.