Beem, John K.
Doubly timelike surfaces - Providence, R.I. : American Mathematical Society, 1969 - 1 online resource (115 p.) - Memoirs of the American Mathematical Society, 1947-6221 ; .
9781470400422 (online)
Doubly timelike surfaces - Providence, R.I. : American Mathematical Society, 1969 - 1 online resource (115 p.) - Memoirs of the American Mathematical Society, 1947-6221 ; .
9781470400422 (online)