Where is the EVP_CIPHER defined?

[sofian sindhi]

Dear all:
I trace openssl recently and I cannot find where the location of EVP_CIPHERs
defined in evp.h.
In evp.h, it is declared as const EVP_CIPHER *EVP_camellia_128_ecb(void);
But where is the trully EVP_camellia_128_ecb(void) located?
I have grepped the source but I cannot get any hint.
appreciate your help,
sofian sindhi