diff --git a/matlab/ols/get_ols_start_end_dates.m b/matlab/ols/get_ols_start_end_dates.m
index d4fb9b313..6f0e4263e 100644
--- a/matlab/ols/get_ols_start_end_dates.m
+++ b/matlab/ols/get_ols_start_end_dates.m
@@ -1,5 +1,36 @@
 function [fp, lp] = get_ols_start_end_dates(Y, lhssub, X, jsonmodel)
 % function [fp, lp] = get_ols_start_end_dates(Y, lhssub, X, jsonmodel)
+% Find the common first observed date and last observed date for X, Y, and
+% lhssub. Impose sample tag if passed to equation
+%
+% INPUTS
+%   Y              [cell array]  dependent variables
+%   lhssub         [cell array]  RHS to subtract from Y
+%   X              [cell array]  regressors
+%   jsonmodel      [cell array]  JSON representation of model block
+%
+% OUTPUTS
+%   fp             [date]        first observed period
+%   lp             [date]        last observed period
+%
+% SPECIAL REQUIREMENTS
+%   none
+% Copyright (C) 2019 Dynare Team
+%
+% This file is part of Dynare.
+%
+% Dynare is free software: you can redistribute it and/or modify
+% it under the terms of the GNU General Public License as published by
+% the Free Software Foundation, either version 3 of the License, or
+% (at your option) any later version.
+%
+% Dynare is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU General Public License
+% along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
 
 fp = max(Y.firstobservedperiod, X.firstobservedperiod);
 lp = min(Y.lastobservedperiod, X.lastobservedperiod);
@@ -26,5 +57,4 @@ if isfield(jsonmodel, 'tags') ...
         lp = lsd;
     end
 end
-
 end