The addresses listed in the two sources are different because they are encoded differently. However, they are essentially the same address. To convert the address to a "canonical" non-user-friendly form, you can use the following code in JavaScript:
new TonWeb.Address('kf-kkdY_B7p-77TLn2hUhM6QidWrrsl8FYWCIvBMpZKprBtN').toString(false);
This will convert the address to the canonical form -1:a491d63f07ba7eefb4cb9f685484ce9089d5abaec97c15858222f04ca592a9ac
,
which is the same as the address listed in the first source.