> 40-XX Sequences, series, summability > 40DXX Direct theorems on summability

40D05 General theorems	40D09 Structure of summability fields	40D10 Tauberian constants and oscillation limits
40D15 Convergence factors and summability factors	40D20 Summability and bounded fields of methods	40D25 Inclusion and equivalence theorems
40D99 None of the above, but in this section

40DXX Direct theorems on summability