[87] Schneider Handb. Laubh. 632. 1906.
[88] Dippel Handb. Laubh. 3:633. 1893.
[89] Jack Gar. and For. 5:64. 1892.
[90] Bailey Cornell Sta. Bul. 38:34. 1892.
[91] Handb. Laubh. 1:633. 1906.
[92] Beitr. Nat. 6:90. 1791.
[93] Handb. Forstb. 11:1392. 1803.
[94] Fedde Repert. 1:50. 1905.
[95] Pl. David 2:33. 1888.
[96] Ill. Bot. His. Mountains and Fl. of Cash. 1:239. 1839.