Ultrasonic Velocities and Densities of L-Histidine or L-Glutamic Acid or L-Tryptophan or Glycylglycine + 2 mol·L-1 Aqueous KCl or KNO3 Solutions from (298.15 to 323.15) K Riyazuddeen; Altamash, T.; Journal of Chemical & Engineering Data 2009, 54, 3133-3139