[65]. See Trans. Am. Society Civil Eng., Vol. 82, 1918, p. 482.
[66]. See Trans. Am. Society Civil Engr., Vol. 41, 1899, p. 76, and Vol. 82, 1918, p. 433, Eng. News, Vol. 74, 1915, p. 400, and Vol. 75, 1916, p. 911.
[67]. Trans. Am. Soc. Civil Engrs., Vol. 82, 1918, p. 433.
[68]. Bulletin No. 31 of the Engineering Experiment Station of the Iowa State College of Agriculture.
[69]. From bulletin No. 31, Engineering Experiment Station, Iowa State College of Agriculture.
[70]. From Bulletin No. 31, Engineering Experiment Station, Iowa State College of Agriculture.
[71]. From Bulletin No. 31, Engineering Experiment Station, Iowa State College of Agriculture.
[72]. From Vouissoir Arches by Cain.
[73]. Baker’s Masonry, 10th Edition, p. 676.
[74]. Business Law for Engineers, C. Frank Allen, McGraw-Hill, 1917; Engineering Contracts and Specifications, J. B. Johnson, McGraw-Hill, 1904; Contracts in Engineering, J. I. Tucker, McGraw-Hill, 1910; The Law Affecting Engineers, W. V. Ball, Archibald Constable, 1909; Law and Business of Engineering and Contracting, C. E. Fowler, McGraw-Hill, 1909; The Economics of Contracting, D. J. Hauer, E. H. Baumgartner, 1915; The Elements of Specification Writing, R. S. Kirby, John Wiley & Son, 1913; Contracts, Specifications and Engineering Relations, D. W. Mead, McGraw-Hill, 1916; Engineering and Architectural Jurisprudence, J. C. Wait, John Wiley, 1912.