Herwich (Herwig, Herpich, Herbig, Herbreg), Christiaen
.A Groundt. Ruggiero. Christian Herwich (Title in the Register: Ruggiero | Viol di gamba Solo à Ground)
D-W, Cod. Guelf. 34.7 Aug.2° (Jakob Ludwig Partitur Buch), pp. 34-35, n° 31
Michael Fuerst, The Partiturbuch Ludwig: An Introduction and Thematic Catalogue, «The Viola da Gamba Society Journal», 4 (2010), pp. 74-102. http://vdgs.org.uk/journal/Vol-04.pdf