         )
     }
 
+    /**
+     Returns US tablespoon `[US tbsp]` volume unit.
+     
+     - author: Michal Konturek
+     */
     public static var us_tablespoon: VolumeUnit {
         return VolumeUnit(
             name: "US tablespoon",

        )
    }

    public static var us_quart: VolumeUnit {
        return VolumeUnit(
            name: "US quart",


extension VolumeUnit {

    /**
     Returns US hogshead `[US hhd]` volume unit.
     
     - author: Michal Konturek
     */
    public static var us_hogshead: VolumeUnit {
        return VolumeUnit(
            name: "US hogshead",
            symbol: "US hhd",
            ratio: NSDecimalNumber(mantissa: 238480942392, exponent: -9, isNegative: false)
        )
    }

    /**
     Returns US barrel `[US bbl]` volume unit.
     
     - author: Michal Konturek
     */
    public static var us_barrel: VolumeUnit {
        return VolumeUnit(
            name: "US barrel",
            symbol: "US bbl",
            ratio: NSDecimalNumber(mantissa: 119240471196, exponent: -9, isNegative: false)
        )
    }

    /**
     Returns US gallon `[US gal]` volume unit.
     
     - author: Michal Konturek
     */
    public static var us_gallon: VolumeUnit {
        return VolumeUnit(
            name: "US gallon",
