Experimental observation of type-B coherent photoproduction of e+e- pairs in a crystal Avakyan, R. O. ; Avetisyan, A. É. ; Gyurdzhyan, V. A. ; Dallakyan, K. R. ; Danagulyan, S. S. ; Darbinyan, S. M. ; Ispiryan, K. A. ; Kizogyan, O. S. ; Margaryan, A. T. ; Sukiasyan, Yu. Z. ; Taroyan, S. P. Abstract Publication: Soviet Journal of Experimental and Theoretical Physics Letters Pub Date: April 1990 Bibcode: 1990JETPL..51..396A