eng_Latn: There have been the classical theories which was developed between 1800 to 1950s.
kan_Knda: 1800 ರಿಂದ 1950 ರ ನಡುವೆ ಹಲವಾರು ಶಾಸ್ತ್ರೀಯ ಸಿದ್ಧಾಂತಗಳು ಅಭಿವೃದ್ಧಿಗೊಂಡಿವೆ.