*Nekrolog. in Mizler, Lorenz. Neu eroffnete musikalische Bibliothek IV/I p. 158-76.  Leipzig, 1754.  

Obituary notice written by C.P.E. Bach and Bach's students, J.F. Agricola and Lorenz Mizler.  It is referenced in most later biographical works.  

An English translation is found in: 

* RESERVE Mus Book       ML410.B1 D24 1998
David, Hans T. The new Bach reader : a life of Johann Sebastian Bach in letters and documents / edited by Hans T. David and Arthur Mendel; revised and enlarged by Christoph Wolff.  New York : W.W. Norton, c1998, p. 295-307. 

ML410.B1 F7 1802a
*Forkel, Johann Nikolaus, 1749-1818.  Ueber Johann Sebastian Bachs Leben, Kunst und Kunstwerke. Fur patriotische Verehrer echter musikalischer Kunst.  Leipzig, Hoffmeister und Kühnel, 1802 [Frankfurt a. M., H. L. Grahl, 1950]

English translations are found in: 

* RESERVE Mus Book       ML410.B1 D24 1998
David, Hans T. The new Bach reader : a life of Johann Sebastian Bach in letters 
and documents / edited by Hans T. David and Arthur Mendel ; 
revised and enlarged by Christoph Wolff.  New York : W.W. Norton, c1998, p. 419-482.

and in: 

ML410.B1 F83 1970                
Forkel, Johann Nikolaus. [Ueber Johann Sebastian Bachs Leben, Kunst, und Kunstwerk. English.] Johann Sebastian Bach; his life, art, and work.   New York, Da Capo Press, 1970.

*ML105 .M42
Mattheson, Johann, 1681-1764.  Grundlage einer Ehren-pforte, woran der tüchtigsten Capellmeister, Componisten, Musikgelehrten, Tonkünstler &c. Leben, Wercke, Verdienste &c. erscheinen sollen. Zum fernern Ausbau angegeben von Mattheson.  Hamburg, 1740.  In Verlegung des Verfassers. Berlin, Kommissionsverlag von L. Liepmannssohn, 1910. 

Mattheson knew Handel personally and wrote the first detailed account of Handel’s life and works. Also scanned and online at: http://imslp.org/wiki/Grundlage_einer_Ehren-Pforte_(Mattheson,_Johann). 

An English translation is found  in:
*RESERVE ML410 H13 D47
Deutsch, Otto.  Handel, a documentary biography. London : A.  and C. Black, 1955, p. 501-506.

*ML410.H13 M2 1975
Mainwaring, John.  Memoirs of the life of the late George Frederic Handel, to which is added a catalogue of his works and observations upon them.  [Amsterdam] : F. Knuf, 1975.

Original London : Dodsley, 1760.  Appeared within months of Handel’s death and features a lengthy discussion of his music. Knuf 1975 is a reprint.  Also found in the  Handel Reference Database  Scroll below dates to find links to digitized texts including the Mainwaring biography.

ML410.H13 C87 1979
Coxe, William. Anecdotes of George Frederick Handel and John Christopher Smith. New York : Da Capo Press, 1979.

Reprint of the London : Bulmer, 1799 publication. Also found in the  Handel Reference Database  Scroll below dates to find links to digitized texts including the Mainwaring biography.