The use of slats with a removable scale for observations of precipitation and deformation of buildings allows the use of wall marks in virtually any range of excess with an accuracy of Class II leveling.
- Tomshin A.A. Rejka dlja opticheskogo opredelenija ordinat // Otkrytija. Izobretenija. Promyshlenye obrazcy. Tovrnye znaki 1969 №31.
- Levchuk G. P. Prikladnaja geodezija. Osnovye metody i principy inzhenero-geodezicheskih rabot. M., 1981.