| Sprau, Benjamin; 1930 Red Book; 1930 | 1930 Red Book | 1930-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1931 Red Book; 1931 | 1931 Red Book | 1931-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1932 Red Book; 1932 | 1932 Red Book | 1932-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1933 Red Book; 1933 | 1933 Red Book | 1933-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1934 Red Book; 1934 | 1934 Red Book | 1934-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1935 Red Book; 1935 | 1935 Red Book | 1935-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1936 Red Book; 1936 | 1936 Red Book | 1936-00-00 | HYDRO | Chief Engineer |
| Sprau, Benjamin; 1937 Red Book; 1937 | 1937 Red Book | 1937-00-00 | HYDRO | Chief Engineer |