In the picture of the linked article he's clearly holding Strang's book - see a picture of it on Strang's site here: http://math.mit.edu/~gs/linearalgebra/ http

In the picture of the linked article he's clearly holding Strang's book - see a picture of it on Strang's site here: http://math.mit.edu/~gs/linearalgebra/ http://math.mit.edu/~gs/linearalgebra/. Also, the campus newspaper reported that the book was Strang's here: http://www.dailytitan.com/2015/10/math-textbook-drives-divide-in-department/ http://www.dailytitan.com/2015/10/math-textbook-drives-divid...