The Trapezoidal method - Math bibliographies - in Harvard style

In-text: (Bourne, 2015)

Your Bibliography: Bourne, M., 2015. 5. Trapezoidal Rule. [online] Intmath.com. Available at: <http://www.intmath.com/integration/5-trapezoidal-rule.php> [Accessed 22 February 2015].

In-text: (Hataker, 2015)

Your Bibliography: Hataker, S., 2015. The trapezoidal rule. [online] The trapezoidal rule. Available at: <http://pages.pacificcoast.net/~cazelais/187/trapezoidal_rule.pdf> [Accessed 22 February 2015].

In-text: (Trapezoidal approximation of area under curve, 2015)

Your Bibliography: Khan Academy. 2015. Trapezoidal approximation of area under curve. [online] Available at: <https://www.khanacademy.org/math/integral-calculus/indefinite-definite-integrals/riemann-sums/v/trapezoidal-approximation-of-area-under-curve> [Accessed 22 February 2015].