Sign M8-H4a “​Ohio Byway - Lincoln Highway Historic Byway” from the <i><a href="https://en.wikipedia.org/wiki/Manual_on_Uniform_Traffic_Control_Devices" class="extiw" title="w:Manual on Uniform Traffic Control Devices">Ohio Manual of Uniform Traffic Control Devices</a></i>.
Ohio Department of Transportation
<cite class="book" style="font-style:normal">(20 January 2023) <i> <a rel="nofollow" class="external text" href="https://www.dot.state.oh.us/roadway/sdmm/SDMMSignFiles/M8-H4a.pdf">Sign Designs and Markings Manual</a></i> (PDF), Ohio Department of Transportation  <small></small></cite>