Vivaldi's Vespers for the Assumption of the Blessed Virgin do not exist as an autonomous composition.
They are a discographic assembly made by Rinaldo Alessandrini from various sacred pieces by Vivaldi.
This is the content of the CD titled Vespers for the Assumption of the Blessed Virgin:
Concerto in F major for two choirs, RV 584, for two violins and two organs (5:34)
Intonatio : Deus in adiutorium (:14)
Responsorio : Domine ad adiuvandum me festina : RV 593, for soloists, two choirs and two orchestras (8:00)
Introduction to the Dixit (in loco antiphonae) : Ascende laeta : RV 635, for soprano and strings (8:00)
Psalm 109 : Dixit Dominus : RV 594, for soloists, two choirs and two orchestras (27:00)
Antiphona : Assumpta est Maria in caelo (:36)
Antiphona to Laudate pueri : Maria Virgo assumpta est (:30)
Psalm 112 : Laudate pueri : RV 600, for soprano and orchestra (25:00)
Antiphona : Maria Virgo assumpta est (:32)
Antiphona to Laetatus sum : In odorem unguentorum (:26)
Psalm 121 : Laetatus sum : RV 607, for choir and orchestra (3:12)
Antiphona : In odorem unguentorum (:30)
Antiphona to Nisi Dominus : Benedicta filia tua Domino (:21)
Psalm 126 : Nisi Dominus : RV 608, for contralto and orchestra (22:00)
Antiphona : Benedicta filia tua Domino (:24)
Antiphona to Lauda Jerusalem : Pulchra es et decora (:24)
Psalm 147 : Lauda Jerusalem : RV 609, for soloists, two choirs and two orchestras (6:29)
Antiphona : Pulchra es et decora (:25)
Ave Maris stella (1:51)
Antiphona to Magnificat (:32)
Magnificat, RV 610a, for soloists, two choirs and two orchestras (17:00)
Concerto in C major : for the Most Holy Assumption of Mary the Virgin : RV 581 (in loco antiphonae) for violin and strings (15:00)
Antiphona : Salve Regina, RV 616, for contralto and two orchestras (17:00).
From the RV numbers, you can notice that these are autonomous compositions written in different years.
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http://www.flaminioonline.it//Biografie/Vivaldi-catalogo-pagina3.html#IX