Drilling.

v.11MAY-OCT 1950; v.13NOV-APR 1951-1952; v.15MAY-OCT 1954; v.16NOV-APR 1954-1955; v.18NOV-APR 1956-1957; v.18MAY-OCT 1957; v.20NOV-APR 1958-1959; v.20MAY-OCT 1959; v.21MAY-OCT 1960; v.21 no.7-13 MY-O(1960); v.24 no.7-13 MY-O(1963); v.25 no.7-13 MY-O(1964); v.26 no.7-13 MY-O(1965); v.27 no.7-13 AP15-O(1966); v.28 no.8-13 MY-O(1967); v.32 no.10-13 JY-O(1971); v.33 no.8-13 MY-O(1972); v.36 no.7-13 AP-O(1975); v.37 no.7-13 AP-O(1976); v.38 no.8-13 MY-O(1977); v.39 no.9-13 JE-O(1978); v.41:8-13 MY-O(1980); v.42:8-13 MY-O(1981); v.21(1959-1960); v.22NOV-APR 1960-1961; v.22MAY-OCT 1961; v.23NOV-APR 1961-1962; v.24MAY-OCT 1963; v.29:1-7 N-AP(1967-1968); v.30:1-6 N-AP(1968-1969); v.31:1-9 N-JE(1969-1970); v.35:1-7 N-AP(1973-1974); v.38 no.1-7 N-AP(1976-1977); v.39 no.1-7 N-AP(1977-1978); v.40 no.1-7 1978N-1979AP; v.41(1979-1980); v.42:1-6 N-AP(1980-1981); index1953-1954 1953-1954