Bonds Models Click on a model link below to view or download the model. The models with a .ltx extension are formatted for traditional LINDO, .lng and .lg4 for LINGO and .xls for What'sBest!. ASSET_LIABILITY_D.lng ASSET_LIABILITY_S.lng BDTBONDT.lng BONDS.xls FINPLAN.ltx MUNBNDN.lng MUNBNDT.lng PBOND.lng SCENARIO.ltx TAXPLAN.ltx