एपीए उद्धरण

Hellwig, G. (1964). Differential operators of mathematical physics. Addison – Wesley.

शिकागो स्टाइल उद्धरण

Hellwig, Gunter. Differential Operators of Mathematical Physics. Addison – Wesley, 1964.

एमएलए उद्धरण

Hellwig, Gunter. Differential Operators of Mathematical Physics. Addison – Wesley, 1964.