Martin, J. L. (1959년 6월 23일). “The Feynman principle for a Fermi system”. 《Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences》 (The Royal Society) 251 (1267): 543–549. Bibcode:1959RSPSA.251..543M. doi:10.1098/rspa.1959.0127. ISSN2053-9169.
Martin, J. L. (1959년 6월 23일). “The Feynman principle for a Fermi system”. 《Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences》 (The Royal Society) 251 (1267): 543–549. Bibcode:1959RSPSA.251..543M. doi:10.1098/rspa.1959.0127. ISSN2053-9169.
Martin, J. L. (1959년 6월 23일). “The Feynman principle for a Fermi system”. 《Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences》 (The Royal Society) 251 (1267): 543–549. Bibcode:1959RSPSA.251..543M. doi:10.1098/rspa.1959.0127. ISSN2053-9169.