| BalanceCheck | Balance Check for Multiple Covariates in Matched Observational Studies |
| CrossMST | Covariate balance checking through the minimum spanning tree |
| CrossNN | Covariate balance checking through the nearest neighbor graph |
| getD | Get intermediate results for CrossNN |
| getDk | Get intermediate results for CrossNN under k-NN |
| getR1R2 | Get intermediate results for CrossMST |
| smokingDist | The distance matrix of the smoking data |