Finding Your Mexican Ancestors is essential to any researcher looking to trace their heritage across the Rio Grande. In it, authors George and Peggy Ryskamp show how easy Mexican American research can be providing detailed descriptions of parish records, civil records, and other types of records common in Mexico.Finding Your Mexican Ancestors is essential to any researcher looking to trace their heritage across the Rio Grande. In it, authors George and Peggy Ryskamp show how easy Mexican American research can be providing detailed descriptions of parish records, civil records, and other types of records common in Mexico.