무료 1일 50건
https://brunch.co.kr/@reading15m/541
아웃룩으로 보내기
https://xlworks.net/mail-send-using-outlook/
워드/한글 + 엑셀 + 아웃룩
https://soulbrain.tistory.com/637
스티비
https://blog.stibee.com/%EB%88%84%EA%B5%AC%EB%82%98-%EC%8B%9C%EB%8F%84%ED%95%98%EB%8A%94-%EC%8B%A4%EC%A0%84-%EC%9D%B4%EB%A9%94%EC%9D%BC-%EB%A7%88%EC%BC%80%ED%8C%85-%ED%8C%81-8%EA%B0%80%EC%A7%80-7bbcd75e8b4b