U.S. Coast and Geodetic Survey, Jones, Ernest Lester, 1876-1929 · Washington : Govt. Print. Off. · leaf 50
J UJ Special Publication fJo. 38. … Fig. 13.—ALLTRIANGULATION STATIONS ARE PERMANENTLY MARKED WITH BLOCKSOF CONCRETE INTO WHICH IS SET A BRONZE TABLET OF THE TYPE SHOWNHERE.
Charts, diagrams, etc
Internet Archive · University of Toronto, Robarts Library · Public Domain Mark 1.0. Free to use for anything.
