Choy, S. "High accuracy precise point positioning using a single frequency GPS receiver" Journal of Applied Geodesy, 5.2 (2011): 59-69. Retrieved 25 May. 2013, from doi:10.1515/jag.2011.008

Choy, S. (2011). High accuracy precise point positioning using a single frequency GPS receiver. Journal of Applied Geodesy, 5(2), pp. 59-115. Retrieved 25 May. 2013, from doi:10.1515/jag.2011.008

Choy, S. 2011. High accuracy precise point positioning using a single frequency GPS receiver. Journal of Applied Geodesy. 5(2): 59-115. Retrieved 25 May. 2013, from doi:10.1515/jag.2011.008