Okla. Stat. tit. 19, § 287

Each register of deeds shall keep an index of deeds direct and inverted, and an index of mortgages direct and inverted, in his office. The index direct and inverted, of deeds and mortgages, shall be divided into columns, with heads to the respective columns, as follows to-wit: GRANTOR - GRANTEE DATE OF FILING WHERE RECORDED DESCRIPTION OF PROPERTY M. D. Y. A.M. P.M. Book Page Lot Blk. Qr. Sec. Tp. R. GRANTEE - GRANTOR DATE OF FILING WHERE RECORDED DESCRIPTION OF PROPERTY M. D. Y. A.M. P.M. Book Page Lot Blk. Qr. Sec. Tp. R. Remarks He shall enter in alphabetical order in the direct index of deeds and mortgages the names of the grantors and in the inverted index of deeds and mortgages the names of the grantees in alphabetical order, and whenever any mortgage bond or other instrument has been released or discharged from record, according to law, the register shall immediately note in both indexes under the column headed "Remarks," and opposite to the appropriate entry, that such instrument has been satisfied. He shall also keep an index, direct and inverted, of the miscellaneous records in the same form as the index of deeds and mortgages.