1. 1) W. A. JANSSEN: Iron Age. 98 (1916), 31
2. 2) W. A. JANSSEN: Iron Trade Rev., 59 (1916) 507
3. 3) W. A. JANSSEN: Foundry, 45 (1917), 15
4. 4) W. A. JANSSEN: J. Am. Foundrymen's Assoc. 25 (1917), 374
5. 5) G. F. COMSTOCK: Iron Age, 105 (1920) 1784