Nigg, C. R.; Motl, R. W.; Wong, K. T.; Yoda, L. U.; McCurdy, D. K.; Paxton, R.; Horwath, C. C.; Dishman, R. K. Impact of Mixed Survey Modes on Physical Activity and Fruit Vegetable Consumption: A Longitudinal Study. SRM 2009, 3 (2), 81-90. https://doi.org/10.18148/srm/2009.v3i2.1092.