In In re B. G.11 Cal. 3d 679, a father and his two children fled Czechoslovakia. (Id. at p. 682.) Shortly thereafter the father died, and the juvenile court awarded the foster parents in California custody of the children. (Ibid.) Later, the children's mother, who had remained in Czechoslovakia, tried to regain custody. (Ibid.) The court held that the government agency responsible for providing notice of the proceedings to interested persons had failed to take reasonable efforts to determine the mother's address in Czechoslovakia. (Id. at p. 689.) The court noted that the government agency had made no effort to obtain her address from the children's grandparents (who were living in California), the Czechoslovakian Embassy or any international organization. (Ibid.) Ultimately, however, the court found that the mother had waived any defects in notice by appearing in the action. (Ibid.)