Macsyma and REDUCE are written in Lisp. The development of those two computer algebra programs started in the mid/end 1960s. They are still maintained today. Th

Macsyma and REDUCE are written in Lisp. The development of those two computer algebra programs started in the mid/end 1960s. They are still maintained today. That makes them over 50 years old. Some history on Macsyma: https://www.sciencedirect.com/science/article/pii/S0747717110001483 https://www.sciencedirect.com/science/article/pii/S074771711... REDUCE: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.153.8827&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.153...