Ref1

https://books.google.com.my/books?id=Weqy__d__xAC&pg=PA199&lpg=PA199&dq=yield+Trifolium+pilulare&source=bl&ots=AiMQ-lwE7p&sig=ACfU3U2D1U4028vjlvn3HLJPQfPlOh_IAQ&hl=en&sa=X&ved=2ahUKEwj28s3-qZzhAhXN73MBHZWCD5YQ6AEwAHoECAgQAQ#v=onepage&q=yield%20Trifolium%20pilulare&f=false