Except as prescribed by the next section, a guaranty must be in writing, and signed by the guarantor; but the writing need not express a consideration.
Okla. Stat. tit. 15, § 324
Guaranty must be in writing - Consideration need not be expressed
R.L.1910, § 1029.
Official source: Oklahoma Legislature. Reproduced from public-domain Oklahoma statutes; confirm against the official source for the current text. Not legal advice.