Combine chicken broth, rice, lemon juice and pepper in a large saucepan. Bring to a boil, then reduce heat to medium and cook until the rice is tender (15-20 minutes). Taste for seasoning. Beat egg yolks in a bowl until frothy. Add several tablespoons of broth to the eggs to heat them, blending well. Slowly stir the egg mixture into the soup. Remove from heat and serve immediately. Garnish with croutons or a tablespoon of yogurt. 4 servings.