Physical Review Letters

Volume	Number	Year
30	23	1973
32	8	1974
32	9	1974
32	10	1974
32	11	1974
32	12	1974
32	13	1974
32	14	1974
32	15	1974
32	16	1974
32	17	1974
32	18	1974
32	19	1974
32	20	1974
32	22	1974
34	4	1975
34	7	1975
34	8	1975
34	11	1975
34	12	1975
34	13	1975