[1] UNIV MICHIGAN, ANN ARBOR, MI USA
[2] JOHNS HOPKINS UNIV, BALTIMORE, MD USA
[3] UNIV CALIF SAN DIEGO, SAN DIEGO, CA USA
[4] VET ADM MED CTR, SAN DIEGO, CA USA
[5] VET AFFAIRS MED CTR, LYONS, NJ USA
[6] UNIV BOLOGNA, BOLOGNA, ITALY
[7] TUFTS UNIV, NEW ENGLAND MED CTR, BOSTON, MA 02111 USA
[8] UNIV MONTREAL, MONTREAL, PQ, CANADA
[9] UNIV MASSACHUSETTS, WORCESTER, MA USA
[10] ST JOSEPH HOSP, ORANGE, CA USA
[11] UNIV MUNICH, MUNICH, GERMANY
[12] CARLE CLIN ASSOC, URBANA, IL USA
[13] MAX PLANCK INST PSYCHIAT, MUNICH, GERMANY
[14] SAN DIEGO SLEEP DISORDERS CTR, SAN DIEGO, CA USA
[15] HARBORVIEW MED CTR, SAN DIEGO, CA USA
[16] MICHIGAN STATE UNIV, E LANSING, MI USA
[17] OSTERSUND HOSP, OSTERSUND, SWEDEN
[18] EASTERN VIRGINIA MED SCH, NORFOLK, VA 23501 USA
[19] SENTARA NORFOLK GEN HOSP, NORFOLK, VA USA
[20] SLEEP CTR H SAN RAFFAELE, MILAN, ITALY
[21] SOUTHMEAD GEN HOSP, BRISTOL, AVON, ENGLAND
[22] COLUMBIA PRESBYTERIAN MED CTR, NEW YORK, NY USA