CLASSIFICATION 
Analysis 
Algebra, 894, 936, 937, 940, 961, 963. 
Quaternions, 962. 
Theory of numbers (Pellian Equation), 948. 
Theory of equations, 897, 905, 907, 914, 925, 932, 938, 950. 
Combinatory Analysis, 903, 915. 
Groups, 903, 918, 934, 957, 965. 
Trees, 895. 
Matrices, 910, 916. 
Invariants and covariants, 908, 923, 926, 927, 932, 942. 
Reciprocants and differential invariants, 933, 943, 944. 
Differential equations, 889, 890, 909, 941, 956. 
Theory of functions, 945, 955. 
Conformal representation, 892, 920, 921, 946. 
Elliptic functions, 891, 901, 935, 966, 967. 
Transformation of elliptic functions, 896, 898, 906. 
Geometry 
Systems of circles, 947, 953, 954, 964. 
Theory of plane curves, 912, 917, 924, 939, 952, 959, 960. 
Tactions, 919.