Erdman Co. is laying off 108 Wisconsin workers because declining revenues and a tough financial market are delaying health care projects. The layoffs, which were reported to the state recently, will affect up to 79 Erdman workers in Madison and 29 in Waunakee. Erdman, formerly Marshall Erdman & Associates, merged with the Charlotte, N.C.-based Cogdell Spencer, a real estate investment trust, in January 2008. Cogdell announced the layoffs as part of its quarterly dividend report to shareholders.