Correct URLs to use https

doc/OnlineDocs/explanation/solvers/gdpopt.rst

@@ -20,7 +20,7 @@ Three algorithms are available in GDPopt:
 
 Usage and implementation details for GDPopt can be found in the PSE 2018 paper
 (`Chen et al., 2018`_), or via its
-`preprint <http://egon.cheme.cmu.edu/Papers/Chen_Pyomo_GDP_PSE2018.pdf>`_.
+`preprint <https://egon.cheme.cmu.edu/Papers/Chen_Pyomo_GDP_PSE2018.pdf>`_.
 
 Credit for prototyping and development can be found in the ``GDPopt`` class documentation, below.
 

doc/OnlineDocs/explanation/solvers/mindtpy.rst

@@ -17,10 +17,10 @@ The following algorithms are currently available in MindtPy:
 
 Usage and early implementation details for MindtPy can be found in the PSE 2018 paper Bernal et al.,
 (`ref <https://doi.org/10.1016/B978-0-444-64241-7.50144-0>`_,
-`preprint <http://egon.cheme.cmu.edu/Papers/Bernal_Chen_MindtPy_PSE2018Paper.pdf>`_).
+`preprint <https://egon.cheme.cmu.edu/Papers/Bernal_Chen_MindtPy_PSE2018Paper.pdf>`_).
 This solver implementation has been developed by `David Bernal <https://github.com/bernalde>`_
 and `Zedong Peng <https://github.com/ZedongPeng>`_ as part of research efforts at the `Bernal Research Group 
-<https://bernalde.github.io/>`_ and the `Grossmann Research Group <http://egon.cheme.cmu.edu/>`_
+<https://bernalde.github.io/>`_ and the `Grossmann Research Group <https://egon.cheme.cmu.edu/>`_
 at Purdue University and Carnegie Mellon University.
 
 .. _Duran & Grossmann, 1986: https://dx.doi.org/10.1007/BF02592064

examples/gdp/small_lit/ex1_Lee.py

@@ -13,7 +13,7 @@
 Taken from Example 1 of the paper "New Algorithms for Nonlinear Generalized Disjunctive Programming" by Lee and Grossmann
 
 This GDP problem has one disjunction containing three terms, and exactly one of them must be true. The literature can be found here:
-http://egon.cheme.cmu.edu/Papers/LeeNewAlgo.pdf
+https://egon.cheme.cmu.edu/Papers/LeeNewAlgo.pdf
 
 """