Using an original survey sample of 103 unquoted Belgian technology-based small firms, the authors examine the capital structure of start-up companies during their consecutive development stages. They find that internal funds, either alone as personal savings or in combination with family and friends, to be the primary source of financing.
Link
http://www.solvay.edu/EN/Research/Bernheim/documents/WP-CEB04-027BozkayaVanPottelsberghe_FinArch.pdf