| S18ACF | Modified Bessel function K0(x) |
| S18ADF | Modified Bessel function K1(x) |
| S18AEF | Modified Bessel function I0(x) |
| S18AFF | Modified Bessel function I1(x) |
| S18CCF | Scaled modified Bessel function exK0(x) |
| S18CDF | Scaled modified Bessel function exK1(x) |
| S18CEF | Scaled modified Bessel function e - |x|I0(x) |
| S18CFF | Scaled modified Bessel function e - |x|I1(x) |