Ratner, J., Calkins, T., Majewski, J. P., Slocum, C., & Bahgat, T. (2006). The building estimator's reference book: A reference book setting forth detailed procedures and cost guidelines for those engaged in estimating building trades (28. edition.). Lisle, Illinois: Frank R. Walker Company.

Ratner, Jerrold, Troy Calkins, Joseph P. Majewski, Christopher Slocum, and Tarek Bahgat. The Building Estimator's Reference Book: A Reference Book Setting Forth Detailed Procedures and Cost Guidelines for Those Engaged in Estimating Building Trades. 28. edition. Lisle, Illinois: Frank R. Walker Company, 2006.

Ratner, Jerrold, et al. The Building Estimator's Reference Book: A Reference Book Setting Forth Detailed Procedures and Cost Guidelines for Those Engaged in Estimating Building Trades. 28. edition. Lisle, Illinois: Frank R. Walker Company, 2006.