Nitrate-depleted conditions on the increase in shallow northern European lakes
  Gesa A. Weyhenmeyer; Erik Jeppesen; Rita Adrian; Lauri Arvola; Thorsten Blenckner; Thomas Jankowski; Eleanor Jennings; Peeter Nõges; Tiina Nõges; Dietmar Straile
            2007
      
  Limnology and oceanography. - 52(2007)4, S. 1346-1353