@article{park_1972, 
  title={On the equivalence of Gaussian processes with factorable covariance functions}, 
  volume={32}, 
  DOI={10.1090/s0002-9939-1972-0290444-6}, 
  publisher={American Mathematical Society (AMS)}, 
  author={Park}, 
  year={1972}, 
  month={Jan}
  }