  We suggest a simple approach to calculate the local density of states that
effectively applies to any structure created by an axially symmetric potential
on a continuous graphene sheet such as circular graphene quantum dots or rings.
Calculations performed for the graphene quantum dot studied in a recent
scanning tunneling microscopy measurement [{\sl Gutierrez et al. Nat. Phys.
\textbf{12}, 1069--1075 (2016)}] show an excellent experimental-theoretical
agreement.
