Blyth, J. E., & Weatherspoon, A. K. :. S. (1992). Michigan timber industry an assessment of timber product output and use. U.S. Department of agriculture.
Cita Chicago (17th ed.)Blyth, James E., i Anthony K : Smith Weatherspoon. Michigan Timber Industry an Assessment of Timber Product Output and Use. Minnestoa: U.S. Department of agriculture, 1992.
Cita MLA (9th ed.)Blyth, James E., i Anthony K : Smith Weatherspoon. Michigan Timber Industry an Assessment of Timber Product Output and Use. U.S. Department of agriculture, 1992.
Atenció: Aquestes cites poden no estar 100% correctes.