These were found in a rant by Dr. Richard Hoagland

• On the Partial Differential Equations of Mathematical Physics, Mathematische Annalen, Vol. 57, 1903, p. 333-355
• On an Expression of the Electromagnetic Field due to Electrons by Means of Two Scalar Potential Functions, Proceedings of the London Mathematical Society, Vol. 1, 1904, p. 367-372